Journal of Scientific Research and Studies Vol. 4(10), pp. 269-281, October, 2017 ISSN 2375-8791 Copyright © 2017 Author(s) retain the copyright of this article http://www.modernrespub.org/jsrs/index.htm

Full Length Research Paper

Enhancement of vegetable plants early growth using products from bacterial degradation of industrial organic

wastes

Amal Fadl Abdelkader1,3*, Eman Afkar 1,4 and Aly M. Hafez2

1Department of Biological Sciences, College of Science, King Faisal University, Al-Ahassa-Hufuf, 31982, Saudi Arabia.

2Department of Chemistry, College of Science, King Faisal University, Al-Ahassa-Hufuf, 31982, Saudi Arabia.

3Department of Botany, Faculty of Science, P.O. Box 381, Ain Shams University, Abbassia, Cairo, 11566, Egypt.

4Department of Botany and Microbiology, College of Science, Bani-Suef University, Egypt.

*Corresponding author. E-mail: amal.abdelkader@yahoo.com

Accepted 18 October, 2017

Nutrient supplements in agriculture are crucial for plants healthy growth and for production of high quality yield. The scope of the present study was identifying and evaluating systematically the possible influential role of the isolated S2 and S4 bacteria on degrading the industrial organic wastes such as skins of chicken and skeleton of shrimp and hence, the bacteria role in nutrient production. The possible impact of the produced extracts of nutrient on vegetable plants early growth and on enhancing soil fertility as compost was further studied. The organic compounds, which originated from bacteria-waste degradation, were used in irrigation of one-month grown crop plants in non-fertile or in partially fertile soils. The candidate cultivars were: Solanum melongena, Abelmoschus esculentus, cucurbita pepo and Petroselinum hortense. GC-MS analysis detected volatile organic compounds after wastes degradation using bacteria, such as Nonanal, 6-Ethyl-2-methyldecane, Tridecane, 2, 3, 8-Trimethyldecane, 3-Dodecanamide, 1-cyclopentyl- Decane and Tetradecane. In addition, some nitrogenous and amid compounds were found such as Cyclo(leucyloprolyl), Cyclo(leucyloprolyl) isomers and Hexadecanamide. Irrigated plants with extracts containing these compounds along with S2 and S4 bacteria resulted in upregulation of the overall seedling height, weight and dry matters compared to irrigation using nutrient broth (NB) and mineral salt medium (MSM) extracts. Stepping forward to the environmental and human health sustainability, we emphasize on: (1) substituting the NB synthetic expensive carbon sources with the natural carbon rich chicken and shrimp skins and, (2) using it for safer utilization by cultivated plants and for plants growth improvement. Key words: Bacteria, biofertilizer, chicken skin, GC-MS, nutrient broth, shrimp skeleton.

INTRODUCTION Authors had discovered that when the proper plant nutrition was ignored, the regulation of growth that contributed at the lower level or whole plant level was not made (McDonald et al., 1996). Fertilization in agriculture originates from various sources; it could be organic, chemical or from microbial action. There is a steadily increasing demand on agronomic utilization of industrial wastes for improving crop plant growth and for solving soil and agriculture problems (Aranda et al., 2010).

However, biofertilizer as a definition hints to the living microorganism containing product that influences plant growth and yield using various mechanisms (Vessey, 2003). The 'biofertilizer' technique is used in this research and refers to the bacteria containing soluble organic nutrient and minerals that could be better utilized by plants than synthetic fertilizers for improving vegetable plant performance. Chicken skin and shrimp skeleton are by-products of poultry and fish industries, respectively.

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270 J. Sci. Res. Stud. Although considered as source of crude nutrients and despite of their richness in protein, amino acids, collagen, gelatin, oils and minerals, millions of tons of these by-products had annually been released to the environment (Sims, 1987; Ghaly et al., 2013). So far, these wastes are not discarded properly as they are merely disposed leading to catastrophic environmental contamination ending with health serious problems (Jayathilakan et al., 2012).

The biofertilizers of industrial wastes had drawn global attention towards recycling of these by-products. In recent studies, the addition of bio-fertilizer to the culture soil of cotton had significantly improved the physicochemical and biological properties of the soil, including soil density, total nitrogen, resistant antioxidant enzymes and increased microbial flora as compared with the effects of organic and chemical fertilizers (Li et al., 2017). In addition, the application of Trichoderma biofertilizers in tomato culture soil has led to the induction of minerals, pigments and increased the growth and leave greenness (Khan et al., 2017). Furthermore, the biofertilizers have improved soil attributes and melon commercial properties via reinforcing N-fixation and nutrient uptake more than the soluble mineral fertilizers (Silva et al., 2016). Likewise, the purple non-sulfur bacteria was used to enhance rice growth and yield and was beneficial in reducing the environmental hazard of methane emission and was a potent alternative to organic and saline fertilizers (Kantachote et al., 2016). On another hand, the non-sulfur bacteria have been also found important in providing the production of growth promoting substances and as bioremediators of soil heavy metals such as cadmium and zinc (Sakpirom et al., 2017). It was early discovered that some endophytic rhizobacteria living on cereal plants from Family: Graminae also acted as excellent biofertilizers, inducing soluble phosphate and fixed nitrogenous compounds (Hafeez et al., 2006).

The dry matter distribution over plant structure is depicting plants life plan, growth, performance and survival. It was reported that accumulation of dry matter is usually balanced and considered as a net result of many physiological processes, such as carbon assimilation, respiration and death of organs. Hence, a number of factors, among which the soil nutrients become the most important as influencing plants dry matter (McDonald et al., 1996). In this study, we investigated the biofertilizers impacts on four economically important crop plants. The eggplant Solanum melongena, which belongs to the Solanaceae family, encompasses 2300 species, that are all economically important (D’Arcy, 1991). Except the United States of America, the eggplant is the third important daily dietary vegetable in the rest of the world, particularly the developing world for its cheap prices and nutritional values. The Abelmoschus esculentus (okra) fruit is used as food in many countries. The mucilage it contains

originated from the dense polysaccharide, which was reported to have industrial and medicinal applications (Tomoda et al., 1980). Recently, the seed extract was used for synthesis of gold nanoparticles and acted as antifungal (Jayaseelan et al., 2013). Cucurbita pepo from the Cucurbitaceae family is known as a highly polymorphic economically important native plant to North America (Ferriol et al., 2003). The fruits vary in characteristics between Species. It is a resistant plant to deterioration having stable seed oil with high quality (Ardabili et al., 2011). Finally, Petroselinum hortense (parsley) is a Mediterranean member plant of the Apiaceae family (Fejes et al., 1998). The plant is economically important and used in traditional medicine as a diuretic, a stomach, an emmenagogue and an abortifacient (Kreydiyyeh et al., 2001).

In principle, this study is exploring the efficacy of S2 and S4 bacterial strains isolated from petroleum nearby soil as biofertilizer following their incubation with chicken and shrimp skin powders. The subsequent early effect of all on the growth and the dry matter of cultivated vegetable plants in non-fertile or partially fertile soils was underlined. This study was novel and important by providing an approach regarding proper recycling of emerging wastes from poultry and fish industries and their potential role regarding promotion of agriculture methods.

MATERIALS AND METHODS

Testing the ability of bacteria to use chicken skin powders and shrimp skin powder as a carbon source

Two bacterial strains were used in this experiment designated as S2 and S4 for easy recognition. Bacteria strains were isolated from soil samples near the petroleum aquifers in the eastern province of the kingdom of Saudi Arabia, Al-Othmaniya region. They grow optimally at 28-30°C and a pH ranging from 6.8-7.2. The bacterial isolates were introduced to the mineral salt medium (MSM) containing 0.2 g/L MgSO4, 0.02 g/L CaCl2, 1.0 g/L KH2PO4, 1.0 g/L K2HPO4, 1.0 g/L NH4NO3, 0.05 g/L FeCl3 and 15 g/L Agar; the pH was adjusted to 7-7.2 (Kim et al., 2003). The medium was amended with 3% chicken chicken skin powders (CSP) or shrimp skeleton powder (SP) as the sole carbon source to support the bacterial growth. Two control sets were prepared; MSM, without carbon source and NB, the nutrient agar medium to compare the intensity of growth. All the treatments were prepared, autoclaved and poured on to Petri dishes under aseptic conditions, inoculated with the bacteria and kept at 30°C for 48 h.

Measurement of the degradation products

To measure the degradation products, mineral salt

Abdelkader et al. 271

Table 1. Growth intensity of S2 and S4 bacterial strains expressed as (+) after inoculation into carbon-free mineral salt medium (MSM), nutrient broth medium (NB), MSM amended with 3% shrimp skin powder (SP), and MSM amended with 3% chicken skin powder (CSP).

Bacterial isolates Growth conditions

SP CSP NB MSM(C)

S2 ++ + +++ none

S4 ++ + ++ none

medium (MSM) is prepared as described above without the addition of agar powders; all the treatment done in a liquid medium. Two sets of four Erlenmeyer conical flasks containing 250 ml MSM were set up as follows: nutrient broth (NB) control 1, the MSM only without carbon source, control 2, MSM containing 3% chicken skin powders (CSP) and MSM containing 3% shrimp skin powder (SP). One set inoculated with S2 and the other set inoculated with S4. All the treatments were incubated at 30°C for over 3 days followed by gas chromatography analysis. Gas chromatographic analysis The technique was conducted to analyze and identify the possible accumulated organic compounds in eight extracts resulting from the biodegradation following S2 and S4 bacteria inoculation into a nutrient broth (NB), MS media (MSM), chicken skin powder (CSP) and shrimp skeleton powder (SP). The biodegraded soluble products were filtered in order to remove any unwanted solid residues. Five millimeters from each extract were extracted by 5 ml chloroform by shaking in a closed conical flask for 3 h. After extraction, the organic phase was collected by using a separation funnel. The obtained organic extract was analyzed by Shimadzu Gas Chromatography Mass Spectrometer (GC-MS) model QP2010 SE equipped with Rxi-5 Sil MS capillary column (30 m length × 0.25 mm ID × 025 um film thickness). The analysis of 1 µl of each extract was performed using the gas chromatography parameters as follows: injector temperature, 250°C; initial oven temperature, 40°C (held for 1 min), increased to 230°C at a rate of 10°C min

−1.

The total time required for one GC run was 25 min. Furthermore, the inlet was operated in the Split less mode, while the MS transfer line was held at 200°C. The carrier gas is high-purity helium with a flow rate 1 ml min

-

1. Lab Solution software was used to control the system

and to acquire the analytical data. Plant material and pot experiment Seeds of the four experimental crop plants; S. melongena, A. esculentus, C. pepo and P. hortense were purchased and surface sterilized using 1% sodium

hypochlorite (NaClO) solution for 5 min and then washed thoroughly with distilled water. Seeds of S. melongena, C. pepo and P. hortense were normally planted in small plastic pods filled with non-fertile soil and were regularly irrigated using S2 and S4 bacterial extracts which produced following bacterial incubation with shrimp skeleton powder (SP) or chicken skins powder (CSP). Seeds of A. esculentus and one set of P. hortense seeds were planted in partially fertile soil with organic matter. Water irrigation is designated as a control (water). Irrigation with bacterial extracts was from nutrient broth (NB) and from mineral salt media (MSM). The plants were left to grow for one month in growth chamber controlled at 25°C temperature. Each treatment was conducted using five replicates.

The seedlings were subjected to height measurements, weighed using local Lab balance and the percentages of their dry weights were recorded after drying the seedlings in Lab oven for one day at 50°C. RESULTS Gas chromatographic analysis of the four bacterial organic matter produced from biodegradation was obtained by using the isolated S2 and S4 bio-fertilizer and showed different organic species including the following hydrocarbons: Nonanal, 6-Ethyl-2-methyldecane, Tridecane, 2,3,8-Trimethyldecane, Tetradecan and 1-cyclopentyl Decane. Also, nitrogen containing species were obtained like different isomers of Cyclo(leucyloprolyl), Dodecanamide and Hexadecanamide (Tables 1 and 2, Figures 1-4).

Figure 1 shows that almost 12 compounds were detected when using NB with either isolated S4 or S2 bacteria. Hexadecanamide and different isomers of Cyclo(leucyloprolyl) were found in high intensity in both cases (S2 or S4). Nonanal peak intensity was significantly higher in NB and CSP media of both S2 and S4 bacteria, while Tridecane and 2,3,8-Trimethyldecane were obtained with nearly the same intensities for the four treatments. The overall intensities were higher in S4 compared to S2 (Figure 5 and 6). Both 3-Dodecanol and Tetradecane were produced in each bacterium following similar trends. Regarding S2, the amended media with CSP posed the lowest peak area for 3-Dodecanol and Tetradecane compounds, whereas SP, CSP and MSM

272 J. Sci. Res. Stud.

Table 2. GC-MS data screening of volatile organic compounds elicited from biodegradation of nutrient broth, MS media, chicken skin powder and shrimp skeleton powder via S2 and S4 bacteria isolated from soil samples near aquifers petroleum.

Peak No. Compound Retention time (min.) Mwt Molecular formula

1 Nonanal 9.09 142 C9H18O

2 6-Ethyl-2-methyldecane 12.06 184 C13H28

3 Tridecane 13.3 184 C13H28

4 2,3,8-Trimethyldecane 14.6 184 C13H28

5 3-Dodecanol 15.29 186 C12H26O

6 Dodecanamide 17.54 199 C12H25NO

7 Tetradecane 15.87 198 C14H30

8 Cyclo(leucyloprolyl) 18.34 210 C11H18N2O2

9 Cyclo(leucyloprolyl) isomer 19.34 210 C11H18N2O2

10 Cyclo(leucyloprolyl) isomer 19.51 210 C11H18N2O2

11 1-cyclopentyl- Decane 20.93 210 C15H30

12 Hexadecanamide 22.25 255 C16H33NO

Table 3. The percentage of dry matter of grown crop plants seedlings in soil including S2 and S4 biofertilizers.

Bacterial strains

Cultivars % Dry matter

Soil fertility Water NB MSM SP CSP

S2

Solanum melongena none 8.20±0.02 9.0±0.21 3.20±0.01 9.30±0.11 10.48±0.02

Abelmoschus esculentus partially 11.10±0.01 11.0±0.22 10.98±0.05 11.20±0.1 26.80±0.32

Petroselinum hortnse. partially 3.0±0.02 10.4±0.11 11.5±0.22 14.13±0.22 14.2±0.03

Petroselinum hortense none 8.68±0.014 14.20±0.22 1.80±0.11 21.70±0.11 34.40±0.44

S4

Solanum melongena none 8.20±0.3 9.50±0.11 6.10±0.21 6.40±0.03 10.10±0.50

Abelmoschus esculentus partially 11.10±0.2 14.90±0.27 8.99±0.02 18.75±0.65 17.24±0.43

Petroselinum hortense partially 3.90±0.12 15.40±0.3 12.84±0.31 20.71±0.54 8.54±0.45

Petroselinum hortense. none 8.68±0.22 11.10±0.031 12.0±0.01 19.40±0.32 23.80±0.65

The two bacterial strains were inoculated into nutrient broth (NB), MS media (MSM), Shrimp skeleton powder (SP), and chicken skin powder (CSP) and incubated before using their extracts in irrigation of plants in either non-fertile or partially fertile soils.

Figure 1. GC-MS chromatogram for (a) S4 and (b) S2 bacteria incubated with NB (For peak detection see Table 2).

Abdelkader et al. 273

Figure 2. GC-MS chromatogram for (a) S4 and (b) S2 bacteria incubated with MS media (For peak detection see Table 2).

Figure 3. GC-MS chromatogram for (a) S4 and (b) S2 bacteria incubated with chicken skin powder (CSP). (For peak detection see Table 2).

have elicited the highest peaks compared to NB for S4. The 6-Ethyl-2-methyldecane was produced with low intensities only when using S4 with the four treatments (Figure 6). Peaks of Dodecanamide were detected in all S2 and S4 culture media, whereas 1-cyclopentyl-Decane was particularly characterizing the NB media of S2 and S4 showing higher intensities in S4 as compared to S2 (Figures 5 and 6). Using of S2 or S4 in SP medium showed the highest intensity of 3-dodecanol and tetradecane. Likewise, each or both SP and CSP media have resulted in a high peak intensity of Hexadecanamide in S2 and S4 (Figures 4- 6).

Comparing different treatments together in S. melongena pot experiment, the weight of one-month old seedling grown in non-fertile soil was relatively higher when the synthetic carbon source NB was introduced into the poor soil. Similar results were obtained when SP and CSP bacterial extracts were used for irrigation as compared to irrigated plants with either water or in the absence of carbon sources (MSM, Figure 7A).

In case of A. esculentus experiment, the plant was sown in partially fertile soil. The weight of seedlings was not changed significantly among the treatments. However, the weight was relatively higher in S2-seedlings

274 J. Sci. Res. Stud.

Figure 4. GC-MS chromatogram for (a) S4 and (b) S2 bacteria incubated with Shrimp skeleton powder (SP). (For peak detection see Table 2).

Figure 5. Average peak areas of replicated measurements (n =3) of extracted compounds by using S2 isolates in NB, MSM, CSP and SP powder (Note that, the intensities of nonanal, tridecane and 2,3,8-trimethydecane are multiplied by 5 times in order to compare to the other detected compounds).

irrigated with shrimp extracts after degradation (Figure 7B).

The grown C. pepo seedlings in non-fertile soil had experienced failure to germinate when irrigated with water or with S2 extracts (data not shown). Alternatively, the weight and length of S4 seedlings were superior when the shrimp has been decomposed by S4, followed

by chicken skin. The lowest weight and length values were determined in the MSM treatment (Figure 7C and D). P. hortense seedlings grown on non-fertile soil, then irrigated with S2 and S4 organic waste extracts, viewed significant seedling length values with SP and CSP extracts compared to water, NB, and MSM treatments.

Abdelkader et al. 275

Figure 6. Average peak areas of replicated measurements (n =3) of extracted compounds by using S4 isolate in NB, MSM, CSP and SP powder. (Note that, the intensities of nonanal, tridecane and 2,3,8-trimethydecane are multiplied by 5 times in order to compare to the other detected compounds).

However, the effect of S2 surpassed that of S4 (Figure 7E). The weight of seedlings was particularly higher upon using S2-CSP treatment (Figure 7F).

When P. hortense grew in partially fertile soil, the seedling weight was significantly higher regarding SP and CSP treatments compared to the control treatments. Moreover, the effect of S4 was higher for SP treatment, whereas S2 effect was the best with CSP treatment (Figure 7G).

The overall percentage data of the dry matter of growing seedlings in biofertilizers extracted from shrimp and chicken wastes using S2 and S4 bacteria isolated from petroleum proves the accumulation of insoluble assimilates in the form of dry matter in S2- and S4-seedlings irrigated with extracts from SP and CSP (Table 3). DISCUSSION This study was conducted to examine the possible role of the indigenous petroleum nearby soil bacterial isolates: S2 and S4 in degrading organic matters released in theenvironment as wastes of industrial poultry and fish wastes and their successive action in extracting soluble nutrients that could be potent in agriculture. The important objective of this study was to make use of the released organic wastes to assist both environmental and human health problems and to replace the expensive carbon source necessary for bacterial growth and for decomposing organic matter with cheaper one. Here, we

investigated the presence of any nutrient constituents in the four media, i.e. NB, MSM, SP and CSP at the end of the incubation period using the GC-MS technique. Nutrient impact on the early growth of candidate vegetable plants, e.g. S. melongena, A. esculentus, C. pepo and P. hortense during growth in non- and partially-fertile soils was also examined.

The data viewed that both S2 and S4 isolates possess high ability to breakdown CSP and SP as natural carbon sources. Nonetheless, we also observed the abundanceof nitrogenous and amide compounds produced from the degradation of NB media which could be referred to the presence of the organic nitrogen rich-peptone in the NB media. However, SP and CSP beside their hydrocarbon contents were also containing nitrogenous compounds, such as Dodecanamide and Hexadecanamide, which seemed to be better utilized by vegetable plants than that of NB media, probably due to their natural source and/or to their concentration which was favored for plant growth. As previously reported, plant growth could be affected by nutrient concentrations and nutrient flux around the root (McDonald et al., 1996). The GC-MS analysis underlined the appearance of twelve volatile organic compounds, some of which possess medicinal and industrial values. For example, the authors have previously reported that 'Nominal' was the volatile organic compound extracted from leaves of the olive tree and characterized by high electro- physiological signals to olive fly (Malheiro et al., 2015). Similarly, the 6-Ethyl-2-methyldecane was detected as volatile compound produced upon degradation of potato

276 J. Sci. Res. Stud.

Figure 7. Growth of irrigated vegetable plants seedlings using extracts from S2 and S4 bacterial biodegradation of nutrient broth (NB), MS media (MSM), shrimp skeleton powder (SP) and chicken skin powder (CSP). (A) Weight of one-month old Solanum melongena seedlings

grown in non-fertile soil, (B) weight of one-month old Abelmoschus esculentus seedlings grown in partially fertile soil and treated for 15 d, (C) weight of one-month old S4-Cucurbita pepo seedlings grown in non-fertile soil, (D) and length, (E) length of Petroselinum hortense grown in non-fertile soil for one month with the treatments, (F) weight of Petroselinum hortense seedlings grown in non-fertile soil for one month with the treatments, (G) weight of one- month old Petroselinum hortense grown in partially fertile soil and fertilized for 20 d.

extracts in fungus containing media (Siddiquee et al., 2012). In addition, Tridecane was the volatile organic compound produced by Specific bacteria to mediate the induction of systemic resistance in Arabidopsis (Lee et al., 2012). Moreover, the Dodecanamide is synthesized by bacteria after contamination with food stuffs and could be detected in plants as one derivative of phenylethylamine pathway which is used as indicator for food quality and validity (Horbowicz et al., 2015). Recently, Dodecanamide was further extracted from the wild Rostellularia diffuse plant as a valuable bioactive compound in pharmacology (Saleem et al., 2017). The Cyclo(leucyloprolyl) isomer is a bacterial important product with inhibitory action against aflatoxins of Aspergillus SP. (Yan et al., 2004). Moreover, the two compounds Tridecane and Dodecanamide were extracted from tea leaves, having antibacterial activity against Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi (Beltagy, 2016). The nitrogenous compound Hexadecanamide was previously extracted from leaves of Piper betle L. in volatile organic form and as antibacterial compound (Nalina and Rahim, 2007) and was also detected in extract of transgenic Nicotiana tabacum root after the bacterial gene glutamate dehydrogenase was transferred from E. coli (Mungur et al., 2005).

As mentioned above, the volatile organic compounds which were extracted by S2 and S4 following their action in SP and CSP media not only had substituted the synthetic carbon in NB media, but had also provoked plants early, better and safer growth. Generally, the natural sources evolved from SP and CSP degradation characterized for being potent having physiological and medicinal importance. They facilitated vegetable plant growth likely through signaling or through microbial elimination. In addition to their nutritional value, they must have also acted as hormones and antioxidants during plant growth.

Comparing the two natural carbon sources together, the activity of shrimp waste in enhancing vegetable plant growth was superior probably due to enclosure of an alternative protein source which was detected before and substituted soybean in feeding hens (Gernat, 2001).

Our data revealed that plants respond to the biofertilizers abruptly, significantly and quite early, as provided after 15-30 days only from the culture date compared to the synthetic carbon media. The eggplant early response was prevailing as long as the carbon was in soil regardless of its source; collected from natural sources e.g. SP, CSP, or even from synthetic carbon e.g. NB. The early growth performance and nutrient assimilate were reflected in the percentage of the dry biomass, which was higher when SP and CSP were used as compared to the other treatments, and with S2 compared to S4 bacteria. The grown A. esculentus for 15 days in partially fertile soil under treatment for a further 12 days with NB, MSM and the biofertilizers prevailed

Abdelkader et al. 277 better growth performance and seedling weight particularly with the chicken skin when S2 was the degrading bacteria. However, the chicken skin data were not sound probably due to the existence of carbon source in the soil before irrigation with the biofertilizers. It seems that S4 products were not effective regarding growth increment as they already present organic matter in the soil and that of the chicken extract were likely antagonistic in their effect with the soil present nutrient. Thus, the seedling weight was less in S4-CSP treatment compared to the other treatments. It was discovered that nutrient proportions could be also the key factor affecting the distribution of dry matter amongst plant organs (Ericsson and Kahr, 1995).

Alternatively, the C. pepo which was grown in non-fertile soil and irrigated using NB, MSM, SP and CSP bacterial extracts for one month had exhibited higher seedlings weights and lengths when S4 was inoculated into the shrimp skin, followed by chicken skin, NB, and the least effect were detected in the absence of carbon in the soil i.e. MSM media. The grown plants in water have failed to grow in non-fertile soil as well as under the effect of S2 biofertilizers plants probably due to an antagonistic condition that could had influenced Cucurbita growth.

Apparently, the 30- days grown P. hortense in non-fertile soil exhibited amelioration of S4-seedlings regarding the length in this order: CSP-SP-NB-MSM. Irrigation using S2-CSP resulted in a pronounced increase in length. The dry mass results of S2-SP plants were matching that of S2-CSP plants. However, S2-SP treatment was the superior in Petroselinum grown in semi fertile soil for 12 days, followed by CSP, MSM, and finally NB. This hints to the possible antagonistic effect of synthetic source with soil organic carbon. Conclusion The present investigation underlined the early vegetable plant response to by-products released from industrial organic waste degradation by S1 and S4 isolated bacteria from soil samples near the petroleum aquifers in Saudi Arabia. Bacterial degradation of chicken skin and shrimp skeleton resulted in production of hydrocarbons, amides and nitrogenous compounds that could substitute the conventional synthetic sources of carbon and nutrients. The outcomes indicated that S2 biofertilizer impact on improving vegetable plant growth was better than S4 biofertilizer. However, all examined plants had benefited from S2 and S4 biofertilizers in a manner dependent on the plant genera, soil fertility, culture period, waste type and the bacterial strain used for waste degradation. In fact, the investigated bacteria isolate are potential candidates for solving environmental problems, in synthesis of cheap biofertilizers, and hence, in maintaining human health. Here, we propose the importance of using S2 and S4 biofertilizers to substitute

278 J. Sci. Res. Stud. synthetic carbon and for enhancing vegetable plant growth.

Acknowledgements

The authors thank King Faisal University, Al-Ahassa, Saudi Arabia for providing facilities and finance.

REFERENCES Aranda E, Sampedro I, Díaz R, García-Sánchez M, Siles JA, Ocampo

JA, García-Romera I (2010). Dry matter and root colonization of plants by indigenous arbuscular mycorrhizal fungi with physical fractions of dry olive mill residue inoculated with saprophytic fungi. Spanish J. Agric. Res. 8:579-585.

Ardabili G, Farhoosh R, Khodaparast MHH (2011). 1053 chemical composition and physicochemical properties of pumpkin seeds (Cucurbita pepo Subsp. pepo Var. Styriaka) grown in Iran. J. Agric. Sci. Tech-Iran. 13:1053-1063.

Beltagy AM (2016). Phytochemical attributes and antimicrobial activity of green tea and rosemary leaves: a comparative study. World J. Pharm. Res. 5:1882-1896.

D’Arcy WG (1991). The Solanaceae since 1976 with a review of its biogeography, pp. 75–138 in Solanaceae III, edited by Hawkes JG, Lester RN, Nee M, Estrada N. Royal Botanic Gardens/Kew, London.

Ericsson T, Kahr M (1995). Growth and nutrition of birch seedlings at varied relative addition rates of magnesium. Tree Physiol. 15:85-93.

Fejes S, Krey A, Blazovics A, Luqasi A, Lemberkovics E, Petri G (1998). Investigation of the in vitro antioxidant effect of Petroselinum crispum (Mill.) Nym.ex A.W.Hill. J. Acta Pharm Hung. 68(3):150-6.

Ferriol M, Pico B, Nuez F (2003). Genetic diversity of a germplasm collection of Cucurbita pepo using SRAP and AFLP markers. Theor. Appl. Genet. 107:271-282.

Gernat AG (2001). The effect of using different levels of shrimp meal in laying hen diets. Poul. Sci. 80:633-636.

Ghaly AE, Ramakrishnan VV, Brooks MS, Budge SM, Dave DJ (2013). Fish processing wastes as a potential source of proteins, amino acids and oils: A critical review. Microb. Biochem. Technol. 5:4.

Hafeez FY, Yasmin S, Arianib D, Rahman M, Zafar Y, Malik KA (2006). Plant growth-promoting bacteria as biofertilizer. Agron. Sustain. Dev. 26:143-150.

Horbowicz M, Wiczkowski W, Sawicki T, Szawara-Nowak D, Sytykiewicz H, Mitrus J (2015). Methyl jasmonate stimulates biosynthesis of 2-phenylethylamine, phenylacetic acid and 2-phenylethanol in seedlings of common buckwheat. Acta Biochim. Pol. 62(2):235-240.

Jayaseelan C, Ramkumar R, Rahuman AA, Perumalb P (2013). Green synthesis of gold nanoparticles using seed aqueous extract of Abelmoschus esculentus and its antifungal activity. Ind. Crop Prod. 45:423-429.

Jayathilakan K, Sultana K, Bawa RAS (2012). Utilization of byproducts and waste materials from meat, poultry and fish processing industries: a review. J. Food Sci. Technol. (4993):278-293.

Kantachote D, Nunkaew T, Kantha T, Chaiprapat S (2016). Biofertilizers from Rhodopseudomonas palustris strains to enhance rice yields and reduce methane emissions. Appl. Soil Ecol. 100:154-161.

Khan MK, Haque MM, Molla AH, Rahman MM, Alam MZ (2017). Antioxidant compounds and minerals in tomatoes by Trichoderma-enriched biofertilizer and their relationship with the soil .environments. J. Integr. Agr. 16(3):691-703.

Kim TJ, Lee EY, Kim YJ, Cho K-S, Ryu HW (2003). Degradation of

polyaromatic hydrocarbons by Burkholderia cepacia 2A-12. World J. Microb. Biot. 19(4):411-417.

Kreydiyyeh SI, Usta J, Kaouk I, Al-Sadi R (2001). The mechanism underlying the laxative properties of parsley extract. J. Phytomed. 8(5):382-388.

Lee B, Farag MA, Park HB, Kloepper JW, Lee SH, Ryu CM (2012). Induced resistance by a long-chain bacterial volatile: Elicitation of plant systemic defense by a C13 volatile produced by Paenibacillus polymyxa. Ploseone. https://doi.org/10.1371/journal.pone.0048744.

Li R, Tao R, Ling N, Chu G (2017). Chemical, organic and bio-fertilizer management practices effect on soil physicochemical property and antagonistic bacteria abundance of a cotton field: Implications for soil biological quality. Soil Till. Res. (167):30-38.

Malheiro R, Ortiz A, Casal S, Baptista P, Pereira JA (2015). Electrophysiological response of Bactrocera oleae (Rossi) (Diptera: Tephritidae) adults to olive leaves essential oils from different cultivars and olive tree volatiles. Ind. Crop Prod. 77:81-88.

McDonald AJS, Ericsson T, Larsson CM (1996). Plant nutrition, dry matter gain and partitioning at the whole-plant level. J. Exp. bot. 47:1245-1253.

Mungur R, Glass ADM, Goodenow DB, Lightfoot DA (2005). Metabolite fingerprinting in transgenic Nicotiana tabacum altered by the Escherichia coli glutamate dehydrogenase gene. J. Biomed. Biotechnol. 2:198-214.

Nalina T, Rahim ZHA (2007). The crude aqueous extract of Piper betle L. and its antimicrobial effect towards Streptococcus mutans. Am. J. Biot. Biochem. 3(1):10-15.

Sakpirom J, Kantachote D, Nunkaew T, Khan E (2017). Characterizations of purple non-sulfur bacteria isolated from paddy fields, and identification of strains with potential for plant growth-promotion, greenhouse gas mitigation and heavy metal bioremediation. Res. Microbiol. 168(3):266-275.

Saleem M, Uduman ES, Rathinam P, Karuru Y, Obili G, Chakka G, Janakiraman AK (2017). GC-MS analysis of ethyl acetate extract of whole plant of Rostellularia diffusa. Pharmacognosy 9(1):70-72.

Siddiquee S, Cheong BE, Taslima K, Kausar H, Hasan MM (2012). Separation and identification of volatile compounds from liquid cultures of Trichoderma harzianum by GC-MS using three different capillary columns. J. Chromatogr. Sci. 50(4):358-367.

Silva WO, Stamford NP, Silva EVS, Santos CERS, Freitas ADS, Silva MV (2016). The impact of biofertilizers with diazotrophic bacteria and fungi chitosan on melon characteristics and nutrient uptake as an alternative for conventional fertilizers. Sci. Hortic-Amsterdam. 209:236-240.

Sims TJ (1987). Agronomic evaluation of poultry manure as a nitrogen source for conventional and no-tillage corn. Agron. J. 79(3):563-570.

Tomoda M, Shimada K, Saito Y, Sugi M (1980). Plant mucilage, XXV. 1) Isolation and structural features of a mucilage, "okra-mucilage F" from the immature fruits of Abelmoschus esculentus. Chem. Pharm. Bull. 28:2933-2490.

Vessey JK (2003). Plant growth promoting rhizobacteria as biofertilizers, Plant Soil 255:571-586.

Yan PS, Song Y, Sakuno E, Nakahima H, Nakagawa H, Yabe K (2004). Cyclo(L-Leucyl-L-Prolyl) produced by Achromobacter xylosoxidans inhibits aflatoxin production by Aspergillus parasiticum. Appl. Environ. Microb. 70(12):7466-7473.

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APPENDIX

Supplementary 1. One-month old Solanum melongena seedlings grown in non-fertile soil with S2 and S4 biofertilizers. Bacteria was inoculated into shrimp skeleton powder, chicken skin powder, NB and MSM.

Supplementary 2. One-month old Abelmoschus esculentus seedlings grown in non-fertile soil and irrigated for 15 d with inoculated S2 and S4 bacteria into shrimp skeleton powder, chicken skin powder, NB and MSM.

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Supplementary 3. One-month old Cucurbita pepo seedlings grown in S2 and S4 bacteria inoculated into shrimp skeleton powder, chicken skin powder, NB and MSM in non-fertile soil. The plate views the MSM seedling death for lack of nutrient, and NB- unsprout seedling due to the diminished soil nutrient.

Supplementary 4. One-month old Petroselinum hortense grown for 20 d in partially fertile soil with S2 and S4 bacteria inoculated into shrimp skeleton powder, chicken skin powder, NB and MSM.

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Supplementary 5. One-month old Petroselinum hortense seedlings grown in non-fertile soil for one month with inoculated S2 and S4 bacteria into shrimp skeleton powder, chicken skin powder, NB and MSM.