Biodelignification of rice straw by Phanerochaete chrysosporium in the presence of dirhamnolipid.
Lignin degradation by white-rot fungi has received considerable attention as a means for reducing accumulation of lignocellulosic wastes in the environment. The stimulatory effect of surfactants on fungal lignocellulose bioconversion also has attracted wide interest. In this study the influence of dirhamnolipid biosurfactant on biodegradation of rice straw by Phanerochaete chrysosporium was investigated. It was shown that the biodelignification process of rice straw can be significantly enhanced by the presence of dirhamnolipid biosurfactant. In particular, the dirhamnolipid at the concentration of 0.007% increased the peak activity of lignin peroxidase (LiP) by 86% without affecting the manganese peroxidase (MnP) activity. The water-soluble organic carbon (WSOC) contents in the straw substrates as well as the microbial growth and activity were effectively improved by dirhamnolipid, while the degradation rate of lignin increased by 54% with dirhamnolipid of 0.007%. Observed chemical structural and morphological changes showed that the straw substrates were delignified in the presence of dirhamnolipid with the formation of terrace-like fragments separated from the inner cellular fibers and the release of simple compounds. Variation partitioning analysis revealed that the dirhamnolipid addition induced a significant straw biodelignification which explained 22.1% (P = 0.013) of the variance.
College of Environmental Science and Engineering, Hunan University, 410082, Changsha, People's Republic of China.
Yun-Shan
YS
Liang
Xing-Zhong
XZ
Yuan
Guang-Ming
GM
Zeng
Chen-Lu
CL
Hu
Hua
H
Zhong
Dan-Lian
DL
Huang
Lin
L
Tang
Jia-Jia
JJ
Zhao
D001673:Biodegradation, Environmental; D006017:Glycolipids / Q000378:metabolism*; D007701:Kinetin; D008031:Lignin / Q000032:analysis / Q000378:metabolism*; D012275:Oryza / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*; D020075:Phanerochaete / Q000737:chemistry / Q000378:metabolism*; D018547:Plant Stems / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D013501:Surface-Active Agents / Q000378:metabolism*
D006017:Glycolipids; D013501:Surface-Active Agents; C051310:rhamnolipid hemolysin, Pseudomonas aeruginosa; D008031:Lignin; D007701:Kinetin