Jai S. Ghosh

Chitobiose production by using a novel thermostable chitinase from Bacillus licheniformis strain JS isolated from a mushroom bed

The thermophilic Bacillus licheniformis strain JS was isolated from a bed of mushrooms, Pleurotus sajor-caju. The organism could produce a novel, single-component, thermostable chitinase that was purified by ion-exchange chromatography using DEAE-cellulose in 7.64% yield and in an 8.1-fold enhancement in purity. Its molecular weight is 22kDa. The enzyme is a chitobiosidase, since the chitin hydrolysate is N(I),N(II)-diacetylchitobiose. The optimum temperature for enzyme activity is 55°C, and the optimum pH is 8.0. It was completely inhibited by Hg(2+) ions whereas Co(2+) ions served as an activator. The thermostability of this enzyme is important in the bioconversion of chitinous waste and for the production of chitooligosaccharides.

Study of thermostable chitinases from Oerskovia xanthineolytica NCIM 2839

The mesophilic organism, Oerskovia xanthineolytica NCIM 2839, was adapted to grow at moderate thermophilic temperatures. At these elevated temperatures, it was found to produce two thermostable chitinases—C1 and C2. These were purified by ion exchange chromatography using DEAE cellulose. The chitinases C1 and C2 were found to be stable in a pH range from 3.0 to 9.0 with 7.5 and 8.0 being the optimum pH, respectively. The optimum temperatures of the activities of C1 and C2 were 50 and 55°C, respectively. These were activated by Mn++ and Cu++and inactivated by Hg++. This is first report of an extracellular thermostable chitinase being produced by O. xanthineolytica NCIM 2839.

Biodegradation of 2-mercaptobenzothiazolyl-(Z)-(2-aminothiazol-4-yl)-2-(tert-butoxycarbonyl) isopropoxyiminoacetate by Pseudomonas desmolyticum NCIM 2112

Abstract2-Mercaptobenzothiazolyl-(Z)-(2-aminothiazol-4-yl)-2-(tert-butoxycarbonyl) isopropoxyiminoacetate is used as supplementary additives in commercial-grade insecticides to compensate for the time factor needed for the actual pesticide chemical to start its action. This investigation describes the biodegradation of 2-mercaptobenzothiazolyl-(Z)-(2-aminothiazol-4-yl)-2-(tert-butoxycarbonyl) isopropoxyiminoacetate by Pseudomonas desmolyticum NCIM 2112. The biodegradation is influenced by other carbon and nitrogen sources and indicates that glucose and lactose are effective at 0.5% concentration whereas NaNO3 and NaNO2 at 0.05%. The percent degradation of 2-mercaptobenzothiazolyl-(Z)-(2-aminothiazol-4-yl)-2-(tert-butoxycarbonyl) isopropoxyiminoacetate was found to be 40%.The pH and temperature optima were found to be 7.0°C and 30°C, respectively. The effect on soil parameters was observed in treated soil and indicates remarkable decrease in soil fertility; the phytotoxicity indicates retarded growth and germination inhibition of treated seeds of Sorghum bicolor and Triticum aestivum. In paddy field the inhibition of germination of Oryza sativa was observed.

Low transition temperature mixtures prompted one-pot synthesis of 5, 10 dihydropyrimido[4,5-b]quinoline-2,4(1 H ,3 H )-dione derivatives

An efficient green protocol has been investigated for the synthesis of pyrimido[4,5-b]quinolines derivatives via one-pot three-component condensation of 4-chloro aniline, aromatic aldehyde and barbituric acid using low transition temperature mixtures as new generation and sustainable solvents. The process was accomplished with the use of greener and recyclable reaction media, simple methodology, easy workup procedures and no chromatographic purification with high yield. This new approach is expected to discover some significance in combinatorial synthesis of biologically active scaffolds.Graphical Abstract