초록
<P>Softwood materials have gained considerable attention because of their abundance and high contents of carbohydrates that can be converted into high value products, such as alternative biofuels. However, during the enzymatic conversion of softwood to biofuels, there is a decrease of cellulase activity that significantly limits the conversion efficiency. This study examined the role of mannanase in recovering lost cellulase activity by relieving the inhibition of mannan on cellulases. Kinetic experiments indicated that mannan competitively inhibited <I>Thermoascus aurantiacus</I> cellobiohydrolase (<I>Ta</I> Cel7A) activity and irreversibly inhibited <I>T. aurantiacus</I> endoglucanase (<I>Ta</I> Cel5A) but had no inhibitory effect on <I>Acremonium thermophilum</I> β-glucosidase (<I>At</I> Cel3A). In spruce hydrolysis (100 g/L biomass) by cellulases, further supplementation of mannanase suppressed the inhibition of residual mannan on <I>Ta</I> Cel5A and <I>Ta</I> Cel7A, and the activities of <I>Ta</I> Cel5A and <I>Ta</I> Cel7A increased by 14.3 and 10.9%, respectively. The increase of <I>Ta</I> Cel5A and <I>Ta</I> Cel7A activity enhanced cellulases hydrolytic action and may benefit the subsequent cellulases recovery process. These results may help to characterize the role of mannanase in the production of alternative biofuels from softwood.</P><P>Mannan-induced inhibition of cellulases was studied, and a potential strategy to recovery the inactivated cellulases was investigated.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ascecg/2017/ascecg.2017.5.issue-6/acssuschemeng.7b00605/production/images/medium/sc-2017-006058_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/sc7b00605'>ACS Electronic Supporting Info</A></P>