Process of rice straw degradation and dynamic trend of pH by the microbial community MC1.
The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen (DO) indicated that the optimum DO during cellulose degradation by microbial community MC1 ranged from 0.01 to 0.12 mg/L. The change model of pH values was as follows: irrespective of the initial pH of the medium, pH values decreased rapidly to approximate 6.0 after being inoculated within 48 h when cellulose was strongly degraded, and then increased slowly to 8.0-9.0 until cellulose was degraded completely. During the degradation process, 15 kinds of organic compounds were checked out by GC-MS. Most of them were organic acids. Quantity analysis was carried out, and the maximum content compound was ethyl acetate which reached 13.56 g/L on the day 4. The cellulose degradation quantity and ratio analyses showed that less quantity (under batch fermentation conditions) and longer interval (under semi-fermentation conditions) of rice straw added to fermentation system were contributed to matching the change model of pH, and increasing the quantity and ratio of rice straw degradation during cellulose degrading process. The highest degradation ratio was observed under the condition of rice straw added one time every five days (under semi-fermentation conditions).
Liu
Jian-bin
JB
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100094, China. liujianbin1981@yahoo.com.cn
Wang
Wei-dong
WD
Yang
Hong-yan
HY
Wang
Xiao-fen
XF
Gao
Li-juan
LJ
Cui
Zong-jun
ZJ
D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002482:Cellulose / Q000378:metabolism*; D005285:Fermentation; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000032:analysis; D012275:Oryza / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis; D018547:Plant Stems / Q000737:chemistry*
D009930:Organic Chemicals; D002482:Cellulose; D010100:Oxygen