Screening Of A Formaldehyde-Degrading Bacteria And Studying On Characteristics Of Enzyme Production

Formaldehyde on human harm has become a well-known fact,Decoration materials lead to indoor formaldehyde pollution is the urgent need to solve the social problems at this stage.This study screens a strain capable of using formaldehyde as the sole carbon source of the bacteria,Optimization of the bacteria enzyme production conditions,Simulation of indoor environment formaldehyde degradation testing.To provide reference for biodegradation of indoor formaldehyde.(1)Soil samples are collected from the waste treatment agent point Shenyang Agricultural University,A strain of bacteria with formaldehyde as the sole carbon source and a strong ability to tolerate formaldehyde is obtained.The number was YX-1,according to observe the micro structure morphology,Physiological and biochemical tests and 16SrDNA molecular sequence,identification of YX-1 is Pseudomonas putida.(2)Toxicity test of YX-1 strain is carried out by using Drosophila melanogaster as the test object.By adding different concentrations of the Drosophila culture medium at 20℃environment of bacteria to study number of surviving days of Drosophila melanogaster.The results show that when the content of YX-1 is different,the longevity of Drosophila has different effects,that is,the greater concentration of the bacteria in the culture medium,the greater the impact on the life span of Drosophila,so the bacteria may affect people’s health poses a potential threat.(3)Optimization of enzyme production conditions of YX-1 strain by single factor test and orthogonal test,optimal culture condition is:peptone 1.2g/L,KH2PO4 3g/L,K2HPO4 4g/L,MgSO4·7H2O 0.02g/L,trace element mother liquor 0.1mL/L;The optimum pH and temperature are 8 and 30 respectively.(4)The enzymatic activity of formaldehyde dehydrogenase is determined by ultrasonic fragmentation method.The enzyme belongs to the intracellular enzyme of YX-1 strain.Response surface methodology is used to study the effect of ultrasonic disruption on enzyme extraction.The results show that the optimum ultrasonic time is 6s,the total ultrasonic time is 298s,ultrasonic power is 82W,the enzyme activity up to 4.967U/mg.(5)A simulated test of formaldehyde degradation is carried out.At room temperature,Extracting the simulated environment containing formaldehyde air by circulating pump,after the degradation of the enzyme in the absorption bottle,the air is recycled into the simulated environment to achieve the purpose of degrading formaldehyde.When the initial concentration is different,with the growth of the cycle time,the formaldehyde concentration continuously decreases until a constant value tends to balance.In our country,indoor formaldehyde concentration limit of 0.1mg/m3,when the concentration of formaldehyde is 1.82mg/m3 in the simulated environment,after 14h to reach national standards,when a formaldehyde concentration of 2.10mg/m3,after 22h to reach national standards.