Studies On Different Effects Of Chiitosan Act On Several Biological

Three microorganisms of lactic acid bacteria, E. coli and yeast, one plant material of mung bean sprouts, one animal material of loach were used in this experiment to study the different effects of water-soluble chitosan on them. To microorganisms, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of chitosan were firstly determined. Then the membrane permeability and bacterial activity-related indicators were determined after MIC and4MIC concentration of chitosan treated on bacterial suspension to have a preliminary study on the inhibition mechanisms of water-soluble chitosan. To mung bean sprouts, the inhibition to the growth of leaf, hypocotyl and radicle were firstly judged after0.1%,0.25%,0.5%,1%,2%water-soluble chitosan solution treated. Then the lipid peroxidation, antioxidant protection enzymes and physiological root activity related indicators were determined after0.01%,0.1%,0.5%,1%water-soluble chitosan solution treated on the green bean radicle to study the effects of water-soluble chitosan on the physiology and biochemistry of green bean. To loach, the96h LC50of water-soluble chitosan was determined firstly by acute toxicity test and its toxicity was evaluated. Then the acute toxic effects, the mucus content of loach and the respiration rate were determined after a treatment of high concentrations (>1g/L) of chitosan solution. Flinally, the genotoxicity of chitosan to loach was detected by measuring the abnormal rate of blood RBC.Main results:(1) The MIC of water-soluble chitosan to lactic acid bacteria, E. coli and yeast are0.02%,0.04%and0.2%. The MBC of water-soluble chitosan to lactic acid bacteria, E. coli and yeast are0.08%,0.32%and1.6%. Chitosan can inhibit the vitality of mitochondrial dehydrogenase of lactic acid bacteria and yeast, but cannot inhibit the vitality of mitochondrial dehydrogenase of E.coli.(2)0.1%,0.25%,0.5%,1%and2%concentration of water-soluble chitosan can inhibit the growth of the leaf, hypocotyl and radicle of the mung bean sprouts at different degree. The greater the concentration, the stronger the inhibition. And the radicle was the most sensitive and accompanied with browning. The treatment of high concentration (0.5%,1%) of chitosan for24h increased the lipid peroxidation and the membrane permeability but didn’t harm the protective enzyme system, nor inhibited its radicle vitality and made them show some resistance.(3) The96h LC100,96h MTC,96h LC50of Water-soluble chitosan on loach is respectively120mg/L,2mg/L,15.45mg/L which belong to low toxicity to loach according to pesticides on fish toxicity grading standards wth the value close to medium toxicity. Chitosan may cause the loach mucus shedding and make it bolted and jumping which increased its breath and finally died of exhaustion. Chitosan has acute toxicity to loach but no genetic toxicity.(4) By comparing the effects of chitosan on five kinds of organisms, we believe that there exists similarities and differences among effects of chitosan on lactic acid bacteria, E. coli, yeast, mung bean sprouts and loach. Chitosan have different degrees of inhibition or toxic effects on five kinds of organisms and the effects on their respiratory metabolism are also different:chitosan can inhibit the metabolic activity of lactic acid bacteria and yeast but not inhibit the metabolic activity of E.coli and mung bean sprouts. Chitosan can stimulate the surface mucus off and caused it move insanely which increased its breath greatly and finally make it die of exhaustion.