Enhanced Biobutanol Production in Batch Simultaneous Saccharification and Fermentation From Agriculture Residues Using Novel Clostridial Fusants
thesisposted on 24.05.2021, 06:49 by Sarkar Begum
A novel approach was introduced for the enhancement of biobutanol production in ABE fermenetation. Thermostable Clostridia species were developed through protoplast fusion between mesophilic and thermophilic Clostridial species. Two parental strains of Clostridia species, Clostridium acetobutylicum (ATCC 4259) and Clostridium beijerinckii (ATCC BA101), along with three fused strains, Clostridium acetobutylicum Clostridium thermocellum (CaCt), Clostridium beijerinckii Clostridium thermocellum (CbCt) and Clostridium acetobutylicum Clostridium beijerinckii (CaCb), were examined for biobutanol production using wheat straw as a feed stock in a batch process of simultaneous saccharification and fermentation (SSF). The objective of the study was to use the thermotolerant fused strains to enhance enzymatic activity during the SSF by raising the incubation temperature and thereby eventually increasing biobutanol production. Economic and residence time analysis of SSF found that addition of cellulase increases the cost of fermentation and prolongs biobutanol production cycle. However, results from the current study indicated that the fused strains, at the higher temperature, were able to produce the required enzymes for the saccharification of wheat straw (i.e., endoglucanase, exoglucanase, and b- glucosidase). This will have a major impact on eliminating costs associated with adding enzymes as raw material to the saccharification process. Fused strain CbCt achieved the highest biobutanol production of up to 14.13 g/L (i.e., a yield of 0.29) was reached at 45°C with total sugar consumption of 82%. Enzymatic activity of CbCt was found to be 61.67 FPU (Filter Paper Unit) which was the highest in comparison with other fused strains evaluated in this study. These results indicate a breakthrough for the technological and economical obstacles associated with industrialization of the SSF process.