12. Feedback inhibition of cellulolytic enzymes during saccharification of cellulosic biomass in order to enhance the productivity

Abstract

Current study revealed inhibitory effect of released end products on the activity of cellulolytic enzymes, both natural and synthetic substrates were compared comparatively.Genetically modified Escherichia coli containing the genes of Thermotogapetrophila for the production of endoglucanse, exoglucanse and ß-glucosidase were provided for this research work production of bioenergy from plant biomas. These clones were named as N₁, X₃ and G₁.These cultures were maintained by streaking these on ampicillin containing LB agar plates and were stored by placing them in cold cabinet at 4°C. Sub culturing. It was demonstrated that accumulation of the end products upto a certain concentration with respect to the specific enzyme loading (U/mL), led to the inactivation of the enzymes in saccharification mixture. Overall percentage saccharification of natural and synthetic substrate due to feedback inhibition of sequentially added cellulolytic enzymes was found 23.6% and 29.4% respectively. Variable concentrations of cellulolytic enzymes were added sequentially in order to overcome the inhibitory effect of the released end products during saccharification. This resulted in a significant increase in percentage saccharification of both natural and synthetic substrate upto 33.6% and 34.5% respectively.

Keywords: Biomass; β-glucosidase; cellulolytic enzymes; Saccharification

http://dx.doi.org/10.19045/bspab.2018.700124