biofuel (experiment 2)
DESCRIPTION
The main objective to carry out this experiment is to investigate the changes of glucose concentration in fermentation process. The yeast strain used in this experiment is commercialized ragi tapai UV spectrophotometer is used to test for the glucose concentration presence. In order to prove the consistency of the experiment, 2 different packets of ragi tapai are used. The findings suggested that ragi tapai is capable of hydrolyzing the tapioca flour into simple sugar and eventually convert them to another product.TRANSCRIPT
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CHANGES OF GLUCOSE CONCENTRATION IN MEDIUM
INOCULATED WITH RAGI TAPAI
Heng Joe Shen and Leo Chin Yin
Department of Chemical Engineering
University of Malaya
50603 Kuala Lumpur
Email: [email protected]
Abstract
The main objective to carry out this experiment is to investigate the changes of glucose concentration in
fermentation process. The yeast strain used in this experiment is commercialized ragi tapai UV
spectrophotometer is used to test for the glucose concentration presence. In order to prove the consistency of the
experiment, 2 different packets of ragi tapai are used. The findings suggested that ragi tapai is capable of
hydrolyzing the tapioca flour into simple sugar and eventually convert them to another product.
Keywords: glucose concentration, ragi tapai, UV spectrophotometer and tapioca flour.
1.0 INTRODUCTION
Tapai is a traditional fermented food found in Asia. The main ingredients in the preparation of Tapai are by
fermenting flour with Ragi powder. Ragi is actually a type of plant known as finger millet and mainly found in
Africa and Asia. Scientifically, it is known as Eleusine coracana. It however, contains a lot of microorganism
includes yeast. Generally, yeast cannot hydrolyze complex starch into simple sugar due to diastatic activity.
Ragi Tapai yeast however; possess active amylase systems that are capable of hydrolyzing starch into simple
sugar and eventually into alcohol through anaerobic process.
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Starch
Gelatinization
Amorphous gel
Liquefaction
Glucose solution
Saccharification
Glucose
Figure 1: Starch structure Figure 2: Hydrolyzation process
2.0 METHODOLOGY
2.1 Apparatus and Materials
Test tubes, test tube rack, pipette, beaker, inoculated shaker and UV spectrophotometer.
Deionized water, tapioca flour, Ragi Tapai yeast, KimWipe paper, tissue paper and standard solution.
3.0 RESULTS
Table 1: Absorbance of standard solution (Set 1)
Glucose concentration
(mg/ml)
Absorbance
1 2 Average Actual (Average – Blank)
Blank 0.010 - 0.010 0.00
0.50 0.114 - 0.114 0.104
1.00 0.242 0.239 0.241 0.231
2.00 0.414 0.416 0.415 0.405
3.00 0.602 0.608 0.605 0.595
4.00 0.812 0.817 0.815 0.805
5.00 - - ERROR -
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Table 2: Absorbance of standard solution (Set 2)
Glucose concentration
(mg/ml)
Absorbance
1 2 Average Actual (Average – Blank)
0.000 0.010 - 0.010 0.00
0.500 0.065 0.063 0.064 0.054
1.000 0.176 0.172 0.174 0.164
2.000 0.440 0.443 0.442 0.432
3.000 0.618 0.618 0.618 0.608
4.000 0.758 0.757 0.758 0.748
5.000 0.929 0.933 0.931 0.921
Graph 1: Graph of Absorbance against glucose concentration
y = 0.1981x + 0.0099 R² = 0.9985
y = 0.1908x - 0.0046 R² = 0.9904
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 4.500 5.000
Sta
nd
ard
ab
sorb
an
ce
Glucose concentration (mg/ml)
Set 1 Set 2
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Table 2: Changes in glucose concentration
Samples
(hours after
fermentation)
Sample A Sample C
Observed
absorbance
Absorbance
(-blank)
Glucose
concentration
(mg/ml)
Observed
absorbance
Absorbance
(-blank)
Glucose
concentration
(mg/ml)
0 0.478 0.468 2.312 0.615 0.605 3.003
1 0.862 0.852 4.250 0.854 0.844 4.209
2 1.119 1.109 5.547 1.039 1.029 5.143
16 0.890 0.880 4.391 0.686 0.676 3.362
18 0.785 0.775 3.859 0.531 0.521 2.579
20 0.819 0.809 4.033 0.376 0.366 1.797
22 0.764 0.754 3.755 0.245 0.235 1.136
24 0.681 0.671 3.336 0.149 0.139 0.651
40 0.398 0.388 1.908 0.074 0.064 0.273
42 0.340 0.330 1.615 0.071 0.061 0.258
44 0.273 0.263 1.277 0.068 0.058 0.243
46 0.234 0.224 1.080 0.064 0.054 0.223
48 0.179 0.169 0.803 0.066 0.056 0.233
Samples
(hours after
fermentation)
Sample B Sample D
Observed
absorbance
Absorbance
(-blank)
Glucose
concentration
(mg/ml)
Observed
absorbance
Absorbance
(-blank)
Glucose
concentration
(mg/ml)
0 0.699 0.689 3.427 0.455 0.445 2.196
1 0.880 0.870 4.341 0.507 0.497 2.458
2 1.096 1.086 5.431 0.526 0.516 2.554
16 0.889 0.879 4.386 0.024 0.014 0.021
18 0.862 0.852 4.250 0.023 0.013 0.016
20 0.873 0.863 4.305 0.028 0.018 0.041
22 0.743 0.733 3.649 0.021 0.011 0.006
24 0.718 0.708 3.523 0.020 0.010 0.000
40 0.438 0.428 2.110 0.021 0.011 0.006
42 0.406 0.396 1.948 0.033 0.023 0.066
44 0.364 0.354 1.737 0.033 0.023 0.066
46 0.305 0.295 1.439 0.036 0.026 0.081
48 ERROR - - 0.037 0.027 0.086
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Graph 2: Graph of Absorbance against glucose concentration
4.0 DISCUSSION
From graph 1, the absorbance of ultraviolet using UV spectrophotometer increase almost linearly with glucose
concentration in the medium. The gradient of the graph is found to be 0.19815 with y-intercept equals to
0.00991. Thus, we can then convert the absorbance rate obtained in sample set A and set C by using the
equation
From graph 2, although the initial glucose concentration of set C (0.615mg/ml) is higher than set A
(0.478mg/ml), glucose concentration in set C are generally lower than that of set A. The possibility of this trend
is that the amount of yeast presence in set C is higher than that of set A. Thus, lower amount of glucose
concentration presence because it has been fermented by the yeast into another product.
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
0 5 10 15 20 25 30 35 40 45
Glu
cose
con
cen
trati
on
(m
g/m
l)
Time after fermentation (hours)
Sample A
Sample B
Sample C
Sample D
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3.1 Errors involved in the experiment
In the experiment, there may be several errors that cause experimental results to deviate from theoretical values.
Inaccurate dilution of the sample with deionized water.
The time lag between obtaining the sample to centrifuge and eventually freeze in the -20ºC freezer. The
glucose concentration may have increase or decrease during the time lag.
The glucose concentration between 2 with 16 hours and 24 with 40 hours are purely predicted by using Excel
software. There may be deviations during the period.
5.0 CONCLUSIONS
1. Both starches are hydrolyzed in a similar trend.
2. Different amount of ragi tapai yeast presence in set A and set C.
3. There is a significant difference in heat flux between starch solution heated using hotplate and microwave
respectively.
6.0 REFERENCES
1. Azmi, A., Hasan, M., Mel, M. Ngoh, C. Single-step bioconversion of starch to bioethanol by the coculture of
ragi tapai and Saccharomyces cerevisiae. Deparment of Chemical Engineering, University of Malaya, Kuala
Lumpur & Biotechnology engineering, Kulliyah of Engineering, International Islamic University Malaysia,
Kuala Lumpur.
2. Saelim, K., Dissara, Y. & Kittikun, A.H. Saccharification of cassava starch by Saccharomycopsis fibuligera
YCY1 isolated from Loog-Pang (rice cake starter). Department of Industrial Biotechnology, Faculty of Agro-
Industry & Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai,
Songkhla, 90112 Thailand.
3. Ko, S.D. Tape Fermentation. Agricultural University, Department of Food Science, Wageningen.
Netherlands.
4. Borglum, G.B. Starch Hydrolysis for Ethanol Production. Miles Laboratories, Inc. Industrial Products
Group, Elkhart, Indiana.
Tim
e / V
olu
me,
t/V
(s/
m3)