Mycelial growth and solid-state fermentation of lignocellulosic waste by white-rot fungus Phanerochaete chrysosporium under lead stress.
Lignocellulosic biomass is an abundant renewable resource difficult to degrade. Its bioconversion plays important roles in carbon cycles in nature, which may be influenced by heavy metals in environment. Mycelial growth and the degradation of lignocellulosic waste by lignin-degrading fungus Phanerochaete chrysosporium under lead stress were studied. It was shown that P. chrysosporium could grow in liquid media with 400 mg L⁻¹ Pb(II), and mycelial dry weight was reduced by 54% compared to the control. Yellow mycelia in irregular short-strip shape formed in Pb-containing media, whereas the control showed ivory-white regular mycelial pellets. Two possible responses to Pb stress were: dense hyphae, and secretion from mycelia to resist Pb. During solid-state fermentation of straw, fungal colonization capability under Pb stress was positively correlated with the removal efficiency of soluble-exchangeable Pb when its content was higher than 8.2 mg kg⁻¹ dry mass. Carboxymethyl cellulase activity and cellulose degradation were inhibited at different Pb concentrations, whereas low Pb concentrations increased xylanase and ligninolytic enzyme activities and the hemicellulose and lignin degradation. Cluster analyses indicated that Pb had similar effects on the different microbial indexes related to lignin and hemicellulose degradation. The present findings will advance the understandings of lignocellulose degradation by fungi under Pb pollution, which could provide useful references for developing metal-polluted waste biotreatment technology.
College of Environmental Science and Engineering, Hunan University, Changsha, China.
Dan-Lian
DL
Huang
Guang-Ming
GM
Zeng
Chong-Ling
CL
Feng
Shuang
S
Hu
Mei-Hua
MH
Zhao
Cui
C
Lai
Yu
Y
Zhang
Xiao-Yun
XY
Jiang
Hong-Liang
HL
Liu
D001673:Biodegradation, Environmental; D005285:Fermentation / Q000187:drug effects; D007854:Lead / Q000032:analysis / Q000633:toxicity*; D008031:Lignin / Q000378:metabolism*; D025282:Mycelium / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D020075:Phanerochaete / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity
D012989:Soil Pollutants; C036909:lignocellulose; D007854:Lead; D008031:Lignin