Basic studies on the utilization of cellulosic biomass, unexploited natural resources, as fermentation raw materials, for the production of industrially useful products.

为了选育能利用纤维素类生物质为发酵原料生产抗生素的链霉菌，从土壤中分离到一株纤维素分解能力强的链霉菌C42。我们构建了一个基因表达盒，包含菌株携带的所有9个纤维素酶基因，以创建用于链霉菌的纤维素酶表达载体。非纤维素分解链霉菌转化与载体分泌纤维素酶，但不能降解纤维素和滤纸相反的C42菌株。我们还从另一种链霉菌中分离了5个编码与纤维二糖利用相关的酶的基因，纤维二糖是纤维素酶消化的最终产物，以构建利用纤维二糖的表达载体。纤维素酶表达的结果表明，提高纤维素酶基因的表达水平是至关重要的，以产生载体，使链霉菌能够诱导降解纤维素分解物质的发酵生产抗生素。

In order to breed streptomycetes that can produce antibiotics using cellulosic biomass as fermentation raw materials, we isolated highly cellulolytic Streptomyces strain C42 from soils. We constructed a gene expression cassette harboring all the nine cellulase genes that the strain carries to create a cellulase expression vector for streptomycetes. Non cellulolytic streptomycete transformed with the vector secreted cellulases but failed to degrade cellulose and filter paper in contrast to the C42 strain. We also isolated five genes encoding enzymes related to utilization of cellobiose, a final product of cellulose digested by cellulase, from another streptomycete to construct a cellobiose-utilizing expression vector. The results on the cellulase expression suggested that it is crucial to enhance the expression levels of the cellulase genes to generate vectors which enable streptomycetes to induce the degradation of cellulolytic materials for the fermentative production of antibiotics.