Production of Bioethanol from Agricultural Wastes Using Residual - MDPI

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Dear Yehezkiel I send you several articles that may be helpful

Low yield of bioethanol is due to following reasons:

1. Low mass transfer

2. Inefficient strain

3. Bioethanol inhibition

4. Selection of yeast strain is major in bioethanol production

Dear everyone, thank you for your answer.

Best regards,

Kurniawan

Ethanol inhibition of food grade yeast is not realistic since the yeast is typically not sensitive for ethanol at 1 %.

Possible causes may be inhibition by for example lactic acid forming bacteria.

The ethanol content shall be raised quickly to inhibit lactic acid forming bacteria (or others) which are typically sensitive to ethanol.

For sterilized systems look for inhibition by co-products of your pre -treatment such as furfural.

Dear Mr. Hans Niessen,

Thank you very much for your advices.

Best regards,

Kurniawan

Dear Y S Kurniawan,

I first congratulate on your work for the production of bioethanol from waste. Since it is an interesting topic, I just want to suggest few things on your work. Based on the raw materials, you please calculate the cellulose presence. Choose the substrate with maximum cellulose content that is most important.

Regarding hydrolysis, crude cellulase enzyme is fine but for large scale production, it is better to go for cost effective methods like dilute acid hydrolysis. If you want to stick on enzymatic hydrolysis then calculate the Beta glucosidase activity and endo, exo gluconase activity, that will be very important to calculate the glucose formation. You should give importance to the production of glucose. More glucose formation is directly related to more ethanol production.

Less formation of ethanol is mainly due to the fermentation process, quantify the glucose formation before fermentation, then use proper yeast Sacchromyces cerevisiae to ferment ethanol. There may be some formation of inhibitors like lactic acid that we cannot control. Soon after the ethanol produced go for distillation immediately with yeast. so select thermo-tolerant yeast for your process to get higher yield.

refer these papers for your reference

Dear Dr. Ramadoss Govindarajan,

Thank you very much for nice answer and your advices for my research works.

Best regards,

Kurniawan

If the glucose contents are less the alcohol contents are going to be low only as the alcohol conversion efficiency is likely to be less than 50% of glucose levels. The other likely possibility may be the growth of contaminants like bacteria or fungi which might also consume the available glucose . Proper sterilization before inoculation with yeast might help. Use of proper/suitable strain strain of yeast could also help to achieve the required alcohol yields.

Dear Prof. Ghanshyam Tandon,

Thank you very much for your advices and kind suggestion.

Best regards,

Kurniawan

the main problem is that hydrolysate not contain enough fermentable sugras so you need to do optimization for enzymatic production as well as hydrolysis and fermentation you can look at my newly puplished paper " Optimization of Cellulolytic enzymes production from local potent fungi using full factorial design for bioethanol production from MFEX-treated rice straw using Klebsiella oxytoca P2 " you can find it on my research gate wall

Inhibition of the saccharomyces cerevisiae due to the improper pH of the medium was the major drawback to reduce the bioethanol yield.In general, Saccharomyces cerevisiae is an acidophilic organism and, as such, grows better under acidic conditions. The optimal pH range for yeast growth can vary from pH 4 to 6, depending on temperature, the presence of oxygen, and the strain of yeast. But, Ethanol's hydroxyl group causes the molecule to be slightly basic. It is almost neutral like water. The pH of 100% ethanol is 7.33, compared to 7.00 for pure water. So the medium pH is increased while ethanol production thereby the medium pH causes Saccharomyces cerevisiae to unfavourable

you have to consider optimum operating condition to enhance the production process