Degradation of lead-contaminated lignocellulosic waste by Phanerochaete chrysosporium and the reduction of lead toxicity.
Lead, as one of the most hazardous heavy metals to the environment interferes with lignocellulosic biomass bioconversion and carbon cycles in nature. The degradation of lead-polluted lignocellulosic waste and the restrain of lead hazards by solid-state fermentation with Phanerochaete chrysosporium were studied. Phanerochaete chrysosporium effectively degraded lignocellulose, formed humus and reduced active lead ions, even at the concentration of 400 mg/kg dry mass of lead. The highest lignocellulose degradation (56.8%) and organic matter loss (64.0%) were found at the concentration of 30 mg/kg of lead, and at low concentration of lead the capability of selective lignin biodegradation was enhanced. Microbial growth was delayed in polluted substrate at the initial stage of fermentation, and organic matter loss is correlated positively with microbial biomass after 12 day fermentation. It might be because Phanerochaete chrysosporium developed active defense mechanism to alleviate the lead toxicity. Scanning electron micrographs with energy spectra showed that lead was immobilized via two possible routes: adsorption and cation exchange on hypha, and the chelation by fungal metabolite. The present findings will improve the understandings about the degradation process and the lead immobilization pathway, which could be used as references for developing a fungi-based treatment technology for metal-contaminated lignocellulosic waste.
Huang
Dan-Lian
DL
College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
Zeng
Guang-Ming
GM
Feng
Chong-Ling
CL
Hu
Shuang
S
Jiang
Xiao-Yun
XY
Tang
Lin
L
Su
Feng-Feng
FF
Zhang
Yu
Y
Zeng
Wei
W
Liu
Hong-Liang
HL
D000327:Adsorption; D000704:Analysis of Variance; D001673:Biodegradation, Environmental; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity; D005285:Fermentation; D007854:Lead / Q000378:metabolism* / Q000633:toxicity; D008031:Lignin / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D020075:Phanerochaete / Q000378:metabolism* / Q000648:ultrastructure; D012037:Refuse Disposal / Q000379:methods*
D004785:Environmental Pollutants; C036909:lignocellulose; D007854:Lead; D008031:Lignin