BIOTECHNOLOGY: Bioethanol Production from Pineapple Waste Solution

This report delves into the production of bioethanol from pineapple waste, presenting a detailed solution and evaluation of the process. The report begins by outlining the materials used, including pineapple peels, enzymes (glucoamylase and α-amylase), and yeast, and explains the five-step fermentation process. The core of the analysis revolves around calculating the ethanol yield coefficient using a specific formula, achieving an optimal yield of 70. The report further discusses the fermentation process at 35°C and the vessels used. The evaluation section assesses the solution's reasonableness, highlighting the sugar content in the waste and the role of enzymes and temperature in successful fermentation. It also addresses potential false positives and negatives, along with factors like inaccurate concentrations and temperature variations that might affect results. The report concludes by suggesting alternative materials for bioethanol production, while still prioritizing pineapple peels.

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Question 4 (Propose a solution)
The yield coefficient of production of bioethanol is obtained from the formula below
The ethanol yield coefficient = Maximumet h anol concentration(grammes per litre)
Utilized glucose (grammes per litre)
Waste products of pineapple peels can be employed to help produce a maximum yield
coefficient of bioethanol. And this protocol can be developed in the laboratory to assess ethanol
and glucose yield from pineapple peels which are considered as a waste. The consequence of the
analyzed quality of wholemeal peels of pineapple from the waste substances and the amount of
saccharification of the amount of produced glucose was predicted (KoffiY., 2013). In the
production of bioethanol from pineapple can be done using the following materials;
i. Pineapple: pineapple peels are majorly obtained from the pineapple edible juice
which is in most cases thrown away as a waste.
ii. Enzymes: There are two major enzymes employed during the hydrolysis of starch.
 Glucoamylase. This enzyme is normally got from Rhizopus and Aspergillus
niger. For this enzyme works best at a temperature of a range 550 -600C
 ά-amylase. Is got from Aspergillus oryzae and Bacillus Licheniformis. The
enzyme is applied to degrade the starch from the wheat substance and it is
stable at a temperature of 900C
 Yeast. This acts as enzyme works best at a 350C to enable the fermentation
occurs.

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Experimentation.
In the production of bioethanol is prepared through fermentation of the wheat since it
contains starch and sugar. This production takes the following five steps.
 Crushing of the pineapple to release the starch component.
 Filtering to remove the solid substances.
 Addition point where water, heat, and enzymes are introduced to enable the conversion
into fermentable sugar.
 Fermentation using the yeast. At this point, it is converted to Carbon (IV) oxide and
bioethanol.
 Rectification and the distillation, at this point cleaning and concentration of the ethanol is
done by distillation and removing the co-product from the bioethanol (MILLER, 2011).
 The final step is the drying of the bioethanol which is also known as dehydration.
From the below equation (i) which shows the fermentation equation during the process, we can
obtain the amount of glucose used during the reaction;
C6H12O6 → 2 C2H5OH + 2 CO2…………………………………………… (i)
Every molecule of glucose is then decomposed into two pyruvates, the process referred to as
glycolysis. The process of glycolysis is expreesed by the following equation.
C6H12O6 + 2 ADP + 2 Pi + 2 NAD+ → 2 CH3COCOO− + 2 ATP + 2 NADH + 2 H2O + 2 H+
............ (ii)
And the amount of ethanol in the solution crushed will highly depend on the freshness of the
pineapple. Averagely the amount of ethanol in the pineapple which gives the concentration was

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obtained to be 140g/litre. For the pineapple, the amount of glu cose employed for the
fermentation is actually very low, which gives a low concentration (Ghosh, 2017). For the
average freshness of pineapple, it is obtained to be about 2 g/litre.
Therefore from the above equation for obtaining ethanol yield coefficient is obtained as below;
The ethanol yield coefficient = Maximumet h anol concentration(grammes per litre)
Utilized glucose (grammes per litre)
The ethanol yield coefficient = 140
2
The ethanol yield coefficient = 70
Having a yield coefficient of 70 is actually optimum yield, 70 yield coefficient is also witnessed
in the case of sugarcane. Basically, the fermentation of the pineapple works best at 350C
temperature, at this temperature, the yeast and other enzymes will work best (Bank, 2010).
The above fermentation process is conducted in the below vessel, with a controlled temperature
at 350C

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Fig 1: Showing the vessels used for fermentation (Ghosh, S. K., 2017)
Question 5. Evaluate your solution
The above-obtained solution is highly reasonable given that the correct formula has been
employed to achieve a reasonable yield coefficient for bioethanol. The waste employed in the
experimental protocol contains a relatively higher amount of sugar content which made it
possible for the fermentation to happen. With the availability of sugar juice, the enzymes and the
appropriate temperature for the process it was highly possible for the fermentation to occur
(Jacobs, 2013).
False positive is the result of which shows specific conditions for the production of bioethanol
condition exists when it does not for sure. While the false negative is a test that incorrectly shows
that a given condition is absent (Jacobs, 2013). During the production of the bioethanol, some
conditions like ά-amylase and a temperature of 800C exist in the process wherein the real sense it
does not. It is the glucoamylase and yeast which are vital for the production of bioethanol and

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temperature of about 350 C which is easily attained is employed and this could easily lead to a
false positive result. For the false negative the presence of oxygen as a necessity for the reaction
could easily false negative result.
The attainment of the correct result may be affected by some factors like inaccurate
concentrations for both glucose used in the reaction and the concentration of ethanol in the
waste. Another source of error in this reaction may be inappropriate temperature used for the
reaction. If the temperature is too high or too low then the reaction will not occur the way it
should supposed to be (West, 2011). There are other alternatives which could be employed to
realize a higher yield coefficient, such alternatives may include the use of the sugarcane peels,
whets, potatoes peals. But the pineapple peels is still the best.

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Bibliography
Bank, S. E. I. D., 2010. Alcohol Fuels Bibliography. 1st ed. Washington DC: The Bank.
Ghosh, S. K., 2017. Utilization and Management of Bioresources. 1st ed. London: Springer.
Jacobs, P. B., 2013. Industrial alcohol: a study of the technology, production, and uses of
alcohol in relation to agriculture. 1st ed. New York: CRC.
KoffiY., B., 2013. Alcohol production from pineapple waste. 1st ed. Hull: Springer.
MILLER, D., 2011. Ethanol Fermentation and potential. 1st ed. Stoke: CRC press.
West, C. J., 2011. Producing bioethanol using the pineapple. 2nd ed. Chicago: Springer.