Induction and Regulation of Cellulase Formation in...
A series of investigations on cellulase formation and its regulation in Trichoderma have been conducted.In this paper we report the strong induction of cellulase by sophorose in EA3-867，a strain of Trichoderma pseudokonigii Rifai.Sophorose，a white needle-shaped crystal，was obtained from the extract of the pods of Sophora japonica L.The cellulase activities（C1，Cxand cellobiase）induced by sophorose，especially its initial rate of increase，were considerably higher than those induced by cellulose.The induction of cellulase by sophorose depended upon the time of addition and the organisms used，and was repressed strongly by glycerol.EA3-867 produced cellulase on a medium with cellobiose（0.5%）faster than with cellulose，but slower than with sophorose，in the last case cellulase was produced in the medium being cultured only for 18 hours.Cellobiose was，presumably，not a true inducer itself.The induction of cellulase by sophorose and cellulose was quite similar both in the extracellular or intracellular components and in the patterns of polyacrylamide gel electrophoresis of cellulase preparations induced by them.On a medium containing rapidly utilizable carbon source such as glycerol or glucose，which were not inducers，Trichoderma EA3-867 produced only a trace of cellulase，which ought to be a constitutive cellulase.On glycerol-mineral nutrients supplemented with cellulose or sophorose，EA3-867 also.produced a small amount of pectinase and amylase，which seem to be constitutive enzymes also.The constitutive cellulase，present on cell surface or released into the medium，hydrolyzes cellulose to cellobiose.The latter might be converted into sophorose or its analogues through some mechanisms unknown in the cell.The sophorose or its analogues thus produced is a powerful inducer for cellulase.The constitutive cellulase may thus play a role in the convertion of the insoluble cellulose into a soluble and hence recognizable“signal”molecule.There have been considerable evidences which indicates that the cellulase formation in Trichoderma EA3-867 was regulated by the induction mechanism and by the catabolite repression mechanism as well.(https://www.daowen.com)
[1]Zhu Yu-sheng and Tan Chang（Cellulase Laboratory，Shanghai Institute of Plant Physiology，Shanghai）
