The effects of acid hydrolysis pretreatment of corn cob on saccharification efficiency and fermentation bio-hydrogen production were investigated by orthogonal test design.The hydrolysis pretreatment of corn cob with dilute sulfuric acid was essential for adequately converting substrate into soluble saccharides and bio-hydrogen.The experimental results showed that acid hydrolysis pretreatment of corn cob was found most effective at hydrolysis temperature of 115℃,sulfuric acid concentration of 1.0%,hydrolysis time of 1.5 h and solid-liquid mass ratio 1∶10,in which both maximum saccharification efficiency of 0.5433 g·(g TVS)-1 and bio-hydrogen yield of 85.8 ml H2·(g TVS)-1 were observed.In addition,the mechanisms of degrading corn cob by acid hydrolysis and hydrogen fermentation were also discussed by means of X-ray diffraction(XRD)analysis and crystallinity calculation.
The pretreatment of bacteria source is one of the key factors affecting the efficiency of bio-hydrogen production.Prior to inoculation,cow dung compost as the natural microbial consortium is treated by following methods:(1)forced aeration combined adding sugar after infrared drying;(2)infrared drying;(3)infrared drying combined forced aeration;and (4)water immersion.The effects of the microbial community on bio-hydrogen production were investigated in a 20 L continuous stirred tank reactor (CSTR).The results showed that the maximum hydrogen production ability,hydrogen content and the rate of hydrogen production was 387.6 ml H2·(g-sucrose)-1,55.5% and 0.5089 L H2·(L·h)-1 at fixed sucrose concentration of 10 g·L-1,operating pH of 5.0±0.1 and the pretreated bacteria source by method (1),respectively.The contents of acetic acid and butyric acid were more than 75% of VFAs in the terminal liquid phase by-product.Furthermore,the image analysis by PCR-DGGE technology showed that there was district difference in the number of electrophoresis band and the strength.The sample,of which the bacteria source was treated by method (1),exhibited two maximum illumination bands,which implies that there exist two kinds of dominant microbial community.
