Studies On The Chitinase Inhibitor

The importance of chitinases in the physiological and developmental processes of fungus and insects makes their inhibitors important targets for potential antifungal and insecticidal agents, as well as antimalarial agents.First of all, this study screened a bacterium producing chitinase. The characteristic of enzyme, such as optimum temperature and pH as well as the effects of metal irons on the enzyme, was studied.Based on the screening model, a marine bacterium producing chitinase inhibitor was screened from the East Sea ZheJiang. This strain was identified as Acinetobacter lwoffii ChI-06. The growth curve and stability of genetics were preliminarily studied.In order to enhance the productivity of the inhibitor, the optimization of the fermentation technology of ChI-06 was systematically carried out in flasks. Under optimum conditions, a maximum inhibitor activity of 65.42% was observed after 6 days cultivation at 28℃on a 180 r/min shaker in 50 mL of fermentation medium containing peptone 10.0 g/L, yeast 2.0 g/L, glucose 5.0 g/L, NaC15.0 g/L, Al(NO₃)₃ 2 mmol/L, marine water extraction 30 g/L with 6% inoculum's sizes. In the study in a 3 L fermentor, using the strategy of decreasing the agitation rate during fermentation, the time course was cut off half and the inhibitor activity was achieved 81.73%, which is 24.93% higher compared to the result in flasks.Preliminary studies show chitinase inhibitor could be saccharide or polysaccharide. The Drosophila-killing trials were conducted with the control of Allosamidin and Chlorfluazuron. With the dose of 0.75 mL, chitinase inhibitor can kill 91.67% flies after 3 days cultivation.