Methanotrophs used in Fruit and Vegetable Preservation

Methanotrophs are a group of microbes with methane as the sole carbon and energy source. Methane Monooxygenase (MMO) is the vital enzyme system in the metabolic process of methanotrophs. Under the action of molecular dioxygen, MMO can catalyze olefin epoxidation reaction. Fruits and vegetables can release ethylene in the storage process, which improving the respiratory intensity of fruit and improving the oxygen permeability of fruit tissue protoplasm, and promoting the fruit respiration and other biochemical processes with oxygen. In this paper, changing the culture conditions can improve the ability of MMO in methanotrophs catalyzed ethylene epoxidation into oxirane. The preservation of fruits and vegetables can apply it. Adding vitamin B12 can increase the activity of MMO. The optimum concentration is 8mg/L. Exogenous electron donor sodium formate can improve the epoxidation capacity of MMO by providing the NADH and making the epoxidation continuous. The optimum concentration of sodium formate is 20mmol/L. In the study,p hosphate can improve the permeability of methanotrophs cells, which increasing the exposure of ethylene to MMO. The reaction rate can be improved. The optimal concentration of phosphate is 10mmol/L. When the three kinds of substances are in the optimum concentration, MMO may have the highest activity in epoxidation.