Enhancing the hydrolysis and acidification of steam-exploded cornstalks by intermittent pH adjustment with an enriched microbial community

Intermittent pH adjustment was used to increase the degradation rate of steam-exploded cornstalks (SEC) and the production of organic acids by an enriched microbial community. The results showed that the degradation rate of SEC was as high as 75% and not affected by the intermittent pH adjustment within the range of 7.0–9.0. However, the total concentration of major water soluble metabolites (acetate and propionate) were increased with pH enhancement, showing the results of 1.86 g L−1 for pH 7.0, 2.04 g L−1 for pH 8.0 and 3.32 g L−1 for pH 9.0 after 84 h of fermentation. Based on 16s rDNA analysis by denaturing gradient gel electrophoresis (DGGE), different strains were dominant due to pH shift by intermittent adjustment, which would consequently cause the change in fermentation pattern. Intermittent pH adjustment was considered to be a useful way to enhance bioconversion potentiality of lignocellulose.