雷竹林存留有机覆盖物高效降解菌株分离及产酶条件优化

 有机覆盖物林地大量存留是雷竹Phyllostachys violascens林退化的主要原因之一。为人工促进有机覆盖物高效腐解，为有机覆盖物促腐制剂研制提供前期研究基础，采用稀释涂平板法和富集培养法从雷竹林地覆盖有机材料（砻糠、稻草）和雷竹林土壤中，初选出具有较强纤维素酶活力的菌株7株，其中，真菌4株，放线菌3株，复选出有机覆盖物高效降解菌株1株（菌株2.1）。经菌落形态和生物学特性分析，菌株2.1属青霉属Penicillium，最佳产酶条件为起始pH 5.0，培养温度30 ℃，培养时间5 d，碳源为稻草秸秆粉25.00 g·L^－1，氮源为牛肉膏2.50 g·L^－1，无机盐为氯化铁（FeCl₃）0.01 g·L^－1和磷酸二氢钾（KH₂PO₄）1.50 g·L^－1。图4表3参20

Selection of strains used to degrade organic mulching materials from Phyllostachys violascens forest and optimization of its enzyme production

Severe degradation of a Phyllostachys violascens forest has occurred from organic mulch residues for years.To artificially promote decomposition of organic mulching material and promote regeneration of bamboo forest,seven cellulase-producing strains,including 4 fungi and 3 actinomycetes,from organic matter and soil of a Ph.violascens forest were chosen using a Congo red cellulose identification culture medium.A filter paper enzyme activity(FPA) as well as colony morphology and biological characteristics were used for the analysis.Results showed that among all selected strains,the FPA of Penicillium spp.(Strain 2.1) was highest.Optimal fermentation conditions were as follows: an initial pH 5.0,a cultivation temperature of 30 ℃,and a fermentation time of 5 d.The optimal cultivation medium for Strain 2.1 was chosen as:straw powder(25.00 g·L-1) for the C source,beef extract(2.50 g·L-1) for the N source,and FeCl3(0.01 g·L-1) and KH2PO4(1.50 g·L-1) for important inorganic salts.