Degradation of corn stalk by the composite microbial system of MC1
GUO Peng , WANG Xiaofen , ZHU Wanbin , YANG Hongyan , CHENG Xu , CUI Zongjun
DOI:
Received March 30, 2007,Revised May 21, 2007, Accepted , Available online
Volume 20,2008,Pages 109-114
- Summary
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The composite microbial system of MC1 was used to degrade corn stalk in order to determine properties of the degraded products as
well as bacterial composition of MC1. Results indicated that the pH of the fermentation broth was typical of lignocellulose degradation
by MC1, decreasing in the early phase and increasing in later stages of the degradation. The microbial biomass peaked on the day
3 after degradation. The MC1 e ciently degraded the corn stalk by nearly 70% during which its cellulose content decreased by
71.2%, hemicellulose by 76.5% and lignin by 24.6%. The content of water-soluble carbohydrates (WSC) in the fermentation broth
increased progressively during the first three days, and decreased thereafter, suggesting an accumulation of WSC in the early phase
of the degradation process. Total levels of various volatile products peaked in the third day after degradation, and 7 types of volatile
products were detected in the fermentation broth. These were ethanol, acetic acid, 1,2-ethanediol, propanoic acid, butanoic acid, 3-
methyl-butanoic acid and glycerine. Six major compounds were quantitatively analysed and the contents of each compound were
ethanol (0.584 g/L), acetic acid (0.735 g/L), 1,2-ethanediol (0.772 g/L), propanoic acid (0.026 g/L), butanoic acid (0.018 g/L) and
glycerine (4.203 g/L). Characterization of bacterial cells collected from the culture solution, based on 16S rDNA PCR-DGGE analysis
of DNAs, showed that the composition of bacterial community in MC1 coincided basically with observations from previous studies.
This indicated that the structure of MC1 is very stable during degradation of di erent lignocellulose materials.
