(139c) Consolidated Bioprocessing of Lignocellulosic Biomass Components Via Synergistic Bacterial Co-Culture Consortia
AIChE Annual Meeting
Monday, November 8, 2021 - 1:12pm to 1:33pm
In the first part, B. subtilis was engineered to breakdown hemicellulose as hemicellulose hydrolysis requires only one enzyme, endo-Î²-1,4 xylanase. Different combinations of signal peptides YwmC, SacC, and AmyE with the two xylanases from Trichoderma resei (Tr) and Bacillus pumilis (Bp) were explored for the selection of an optimal design. The supernatant of the engineered strain SSL26 harbouring YwmC-XynA (Bp) displayed a 2-fold increase in endoxylanase activity. In situ depolymerization of xylan with SSL26 resulted in a maximum xylose titer of 15 g/L. As a final step, a B. subtilis: E. coli consortia was developed to break down xylan and simultaneously produce succinate from xylose in a single pot achieving a succinate yield of 3.7 g/L from 10 g/L xylan.
Secondly, for cellulose breakdown two major celluloses required are Î² glucosidases (Bglu) and endoglucanases (Eglc). Similar to previous work combination of signal peptides YwmC, SacC and AmyE with two Î² glucosidases were developed. AmyE- Bglu showed 6 folds higher activity compared to wildtype in pNPG assay. Similarly, endoglucanases constructs were developed with Bglc, YwmC, NprE signal peptide library to demonstrate complete breakdown of cellulose using Î² glucosidases and endoglucanases secreting strain cocultures.We envision that the two approaches together will play a major role in providing alternatives for improving the economics of the biorefinery.