INTRODUCTION

A wide variety of enzymes are produced by the fermentation of solid or liquid wastes & co product. In class of hydrolases, amylases, cellulases & hemicellulases, pectinases, proteases & lipases are most important enzymes in the processing of various food wastes. The feed mixture of these processes would usually contain the main compounds targeted for degradation or conversion by the enzyme. For example, in the case of pectinase enzyme, a pectin containing mixture is required as feed in the fermentation.

The majority of these hydrolytic enzymes act on O-glycosyl compounds & are used for degradation of polysaccharides, while lipases & peptidases hydrolyse carboxylic ester bonds & peptidases hydrolyse carboxylic ester bonds & peptide bonds respectively. These substances occur in almost all types of wastes & co-products from food processing. Therefore their degradation is extremely important & highlights the need for commercial quantities of these enzymes. The most cost effective way to obtain these enzymes is to synthesis them onsite using the same substrate i.e. simultaneous conversion of biomass & production of biocatalyst is undoubtedly beneficial, moreover these system allow much higher flexibility in processing. The other benefit is the possible adaptation of the species to the particular substrate, resulting in higher enzyme activity.

Food wastes & co-product are also suitable materials for the production of other important industrial enzymes. A few examples are fumarase & aspartase production on molasses by Erwinia species for the bitransformation of fumaric acid into L-malic acid & L-aspartic acid respectively.

ENZYME MICRO ORGANISM WASTE PRODUCTα - amylase Bacillus coagulans

Bacillus subtilisCellulomonas sp.

Wheat branBanana fruit stalkWheat bran

cellulases Phanerochate chrysosporiumTrichoderma reesi

Soy hullRice straw

hemicellulases Botyris cinerea Wheat strawxylanases Trichoderma harzianum Rice/wheat strawpectinases Thermoascus aurantiacus

Aspergillus nigerOrange bagasseApple pomace

lipase Penicillium simplicissimumP.restrictum

Babassu cakeBabassu oil cake

β -N-acetylhexosaminidase Verticillium silage lecanii Shrimp waste

Acid Compounds:-

Various acid compounds used as acidifying agents in the food industry are synthesized based on food waste or co products. Two of the most important are citric acid and lactic acid. Citric acid was manufactured for example by Aspergillus niger on apple pomace in apacked bed bioreactor, but it was found that ram horn pepton is also a suitable protein source using the same strain. Lactic acid production from dairy co-product whey is a traditional technique where lactose content is converted by bacterial species.

Biodegradable polymer

Biodegradable polymer are possible products in glycerol processing is the byproduct of, for example, fat splitting or biodiesel production. Among these green polymers, a important group are the polyester alkanoates & polyesters of 1, 3-propanediol which can be produced not only from glycerol, but also from other food wastes & co-products. In the case of PHAs, the length of alkyl chain may be varied but butyrate is the most favourable compound. Its fermentation, for example on sugar beet molasses,can be achieved by Pseudomonas cepacia or on cheese whey by Azotobacter vinelandii or on molasses & whey by Rhizobium meliloti. I is possible to use palm oil effluent for the production of PHAs. Japanese researchers described atwo-stage process. In the first stage, anaerobic trattment of the waste by palm oil sludge was carried out o obtain organic acids, particularly acetic & propionic acid.

Microbial fat

Microbial fat provides an alternative to plant and animal fats and oils can also be manufactured from food wastes. The biomasses contain triglycerides and proteins.

Enzymatic processes and enzymatic extraction

Glucose

Glucoseis the most popular conversion product from food wastes since glucose is the monomer for cellulose and starch. Cellulose degradation is usually carried out by complex cellulolytic enzyme preparations containing several types of cellulases Trichoderma reesei are considered to be the best source of cellulose enzyme. However the mixture should often be supplemented with β glucosidase enzyme to enhance the hydrolytic process. Any kind of cellulose containing waste or co-product is considered for glucose production e.g. rice, wheat andrye straw.these substrates need pre-treatment in most cases.

Starch is much easier to degrade than cellulose, thus the majority of the glucose comes from various starch-containing waste sources, as produced in potato, cassava and corn manufacturing. Amylase mainly alpha and beta amylases from various are used for enzymatic starch hydrolysis.

Recently selection of thermostable amylaseenzyme has been the focus of research in this field. According to the cost analysis of these processes, enzymes are the most expensive materials. To reduce the cost on site enzyme production is worthy of further study and development as mentioned above. In the bioreactors the enzyme reaction and separation of the inhibitiory product takes place simultaneously in one unit. The differences in size of the substrate and the product make separation possible by a suitable porous membrane, this is able to reject long polysaccharide chains as well as the biocatalyst, while the product passes through the membrane easily. In such a system continuous uptake of substrate and release of product without loss of enzyme can be achieved. Moreover, higher effectiveness can be obtained in this particular system because of the lack of product inhibition.

Ethanol

Ethanol is the one of the most important glucosebased products and is either available as an ingredient of wastes and co-products in food industry or can be obtained by hydrolysis from wastes containing polysaccharides. Several technique have been developed according to the raw material used. One of the simplest examples is the direct fermentation of molasses b Sacchromyces cerevisiae.

Protein hydrolysates

Protein hydrolysates can be produced by protease enzymes. A detailed method for the manufacture of glatine and gelatin hydrolysate is described by brich et al using collagen rich wastes from abattoirs. An alcalase enzyme preparation is used at atemperature of 28 degree celcius and the conditioning time is 6-24h. gelatin hydrolysates are produced by hydrolysis using Alcalase and Neutralase preparations recently , keratinases Paecilomyces marquandii. Doratomyces microspores or chryseobacterium are able to degrade feather with an acceptable reaction rate, this is regarded as an extremely high-impact finding due to the huge amount of feather produced as waste worldwide. Although feather in its original form is considered as a low biological value protein source-due to its deficiencies in nutritionally essential amino acids like methionine, lysine, histidine and tryptophan-the feather meal obtained by thermal processing has been incorporated into the diets of certain animals. Microbiological degradation of feathers however may enhance the nutritional value of feather protein hydrolysate, since the biomass could autolytically contribute to the protein and amino acid content of the feather meal.

Proteases are also used for bioprocessing of other enormous waste mass i.e. crustacean shells. Deproteinisation of shrimp and crab shells has been carried out using the Alcalase enzyme preparation and resulted in avaluable chitin source. Recently, an enhanced method was presented where protein hydrolysate can be recovered as well, thus the effectiveness of the process is improved.

Other types of animal wastes may be similarly good sources of protein hydrolysates.the protein content of these materials can be hydrolysed by various commercial protease enzyme preparations or by different endo and exopeptidases from Aspergillus and Bacillus species.

Utilization of these protein hydrolysates can be divided into two main areas according to whether the nutritional or the biodegradable properties are exploited. Protein hydrolysates can be used either as nutrient sources in media for micro-organisms and feed supplement for higher animals or as components for polymer modifications.

Natural flavor compounds

Natural flavor compounds can be synthesized from a co product formed in the distilleries. It is called fuel oil and contains ehtnaol and short chain alcohols. Volatile flavor esters can be manufactured if these alcohol. Volatile, flavor esters can be manufactured if these alcohol compounds are reacted with short chain acids,resulting in low molecular weight esters. The reaction is catalysed by lipase enzyme and can be carried out in the organic solvent or in the solvent free system.

Biolubricans

Biolubricants can also be manufactured from fuel oil. In this case, longer chain acids compounds should be used in the esterification reaction. The process can be carried out by acidic or enzymatic catalysis. The drawback of acidic catalysis is that acid traces may remain in the product, which causes corrosion during utilization. By applying enzymatic catalysis this can be avoided. The biolubricants obtainedare not onl derived from natural renewable source,but also be degraded biologically.

Similar biolubricants can be produced by enzymatic extraction of ethanol by fatty acids. Ethanol recovery from the aqueous fermentation broth can be realized by the extraction using for example oleic acid with simultaneous esterification by lipase enzyme. In this way ethyl oleate is manufactured while ethanol inhibition is avoided.

According to tribological tests, these types of biolubricants can be characterized as lubricant having a low flash point, low pour point, high viscosity index.

Galacturonic acid

Galacturonic acid is an acidifying agent in foods and the monomer of pectin molecules. Thus pectin containing co-product and waste can be processed to recover the pectin. Sugar beet pulp is one of the raw materials most often used. When pectin is extracted from sugar beet pulp by hot water, the process can be promoted by using pectinase enzymes. In this way pectin becomes more soluble, its viscosity is decreased and the yield of the enzymatic extraction is much higher. If the aim is recovery of galacturoinc acid, complete degradation of pectin can be carried out. However controlling the enzyme action may result in partial degradation where soluble pectin can be obtained.

Utilization of protein hydrolysates

SOURCES UTILISATIONRam horn Medium for aerobic becteriaHake (merluccius hubssi) filleting waste Nutrient source in media for bacteria and archaeShrimp ( pandalus borealis) wastes Feed supplement for salmonid fishesShrimp( P. semisulcatus) head wastes Animal/aquaculture feed formulationSardinella aurita fish wastes Nitrogen source for Rhizopus oryzaeLeather waste of tanning Modification of linear- low-density polyethylene

polymerLeather waste Modification of polyvinyl alcohol filmShrimp head silage Protein source for nile tilapiaFish wastes and feather Protein sources for sea bass fry

References:-

1. ABDEL-SATER, M.A and El-Said, A.H.M(2001), Xylan decomposing fungi and xylanolytic activity in agricultural and industrial wastes. Int biodetector biodegrade.

2. Keith waldron, Handbook of waste management and coproduct recovery in food prcessing,vol1,chapter-9.pag no 9-9.2

Assignment

On

Enzyme for waste - treatment

Submitted to:- Submitted by:-

Lect. Deepak Mudgil Sandeep khanna

Dept of Food Tech. (09082012)

G .J.U HISAR Msc 2nd year(Food Tech.)