VOLUME 13 (Supplement)

Physico-chemical characterization of a recombinant endoglucanase from a clone derived from a mixed microbial culture from mudspring water of Mt. Makiling, Laguna, Philippines

The endoglucanase gene harbored in Escherichia coli BL21 clone pEngl-24-21-63 developed in another study expressed the endoglucanase protein, MM-Engl in an autoinduction medium. The expressed endoglucanase protein, MM-Engl was obtained from a mixed culture resulting from cellulose enrichment of mudspring water from Mt. Makiling, Laguna, Philippines, through culture-independent molecular based approach. The protein was partially purified by ammonium sulfate precipitation at 60-80% saturation. The partially purified endoglucanase (PPEndo) was shown to be both acid and thermostable having an optimum temperature of 80 °C, thermal stability from 30 to 80 °C, optimum pH of 3.0 and pH stability from 2.0 to 6.0 based on carboxymethylcellulase (CMCase) activities. The enzymatic activities of the partially purified endoglucanase was greatly enhanced by Mg²⁺ > K⁺ > Cu²⁺ ions, while negatively affected by compounds and ions, EDTA > Mn²⁺ > SDS > Zn²⁺. Highest amount of reducing sugars was released using CMC as substrate as compared against cotton, filter paper and xylan.. The high resistance of MM-Engl to changes in pH and temperature makes it well suited for application in lignocellulose bioprocessing for bioethanol production and as an enzyme component in the feed industry. The stability of the enzymes can reduce the need of cooling the reaction mixture from the previous high temperature step which could hasten the reaction process and reduce production costs.