1Soils, Water and Environ. Research Institute, Agricultural Research Center, Dokki, Giza, Egypt
2Faculty ot Agriculture, Cairo University, Giza, Egypt
Abstract
Chilinolytic bacterial candidate was isolated from mature compost and purified. The isolate was identified as Streptomyces nigntaciens Optimization of growth conditions (peptone N source, 45 °C, pH 9, femientor agitation speed 300 rpm, air flow rate 1 L./min, 48 hours) to obtain the highest chitinolytic activity, under laboratory scale conditions, led to chitinase production increment expressed as chitinolytic activity, from 58.816 U/ml up to 2129 U/mi (36 times). Chitinase production in the fennentor was achieved on local chitinic wastes and the resulting crude enzyme was subjected to partial purification steps (ammonium sulphate precipitance and chitin affinity). The resulting partially purified chitinolytic fractions were separated. Three partially purified chitinases were separated from the supernatant (SUP) named Si, 52 and 53 of 14142, 616,1 and 641.3 U/mg activities, respectively. From the chitinic debris, two partially purified chitinases having a high affinity to chitin were separated and named P1 and P2 of 748.6 and 5344.3 U/mg activities, respectively. The optimization of temperature revealed the superiority of P2 fraction, as the chitinolytic specific activity increased from 3070.700 U/mg at 37 °C to 9126.421 U/mg at 45 °C raising the purification fold to 2.97 and its yield reached 4 %. The P2 optimum enzymatic conditions for hydrolyzing colloidal chitin were found to be pH 10 and substrate concentration of 22 mg/ml.
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