Bioprospecting Microorganisms by Protoplast Fusion to Obtain Economically Important Products by Jui Dave, Pankti Jain and Shanmukhi Rao

The aim of the present investigation is to obtain superior strains with increased activity of industrial enzymes like glucose isomerase (GI), rennin like enzyme and chitinase through protoplast fusion. Protoplasts were obtained by using lysozyme and fusion was carried out using polyethylene glycol prepared in STC buffer. The protoplasts were confirmed by cell wall staining (Dyar’s method) and screened by growth on selective media containing combination of specific antibiotics. As Streptomyces griseus, S. griseoruber and S. olivaceus are potent producers of GI, they were selected as parental strains for fusion. Three fusant strains were obtained, namely, GIf1 from fusion of S. olivaceus and S. griseus, GIf2 from S. olivaceus and S. griseoruber and GIf3 from S. griseus and S. griseoruber. Among the three fusants, the strain GIf3 showed maximum GI activity which was 1.5 times more than the parent strains. Rennin like enzyme is extensively used in dairy industry to produce cheese from milk. Among the three fusants, namely, Rf1, Rf2 and Rf3, which were all obtained by fusion of Lactococcus lactis and Lactobacillus planatarum, the fusants Rf1 and Rf3 produced 1.3 times more rennin like enzyme than the parent strains. Chitinase, which catalyses the breakdown of chitin, finds immense application in agriculture and pesticide industry. Strains with higher chitinase activity were to be obtained by self fusion of Trichoderma harzianum. However this part of the work was not carried out due to lack of lysing enzyme, Novzym 234, used for removal of fungal cell wall.