The Initial Research Of Identification About Halophilic Bacteria And Its Metabolite

Halophilic bacteria is a kind of prokaryotic microorganisms that can tolerate high salt environment.They are diverse and widely distributed.As a new type of microbial resource with great application prospects,halophilic bacteria have special physiological structures and metabolic mechanisms,and also produce many biologically active substances with special properties.Therefore,their research has both theoretical significance and application value.In this paper,a strain capable of producing extracellular sticky metabolites was screened from the culture waste of Dunaliella salina,and the strain was determined to be tropic by morphological observation and molecular biological identification,spectral analysis and metabolomics analysis.Strain YZ1(Halomonas sp.YZ1,YZ1),a Gram-negative bacterium,can use glucose,lactose,sodium citrate as the sole carbon source for growth,and is more sensitive to chloramphenicol and ampicillin;optimal growth temperature is 30～40℃,pH is 7.0～8.0,NaCl concentration is 30～150 g/L.According to the tolerance to salt concentration,strain YZ1 belongs to moderate halophilic bacteria.Under salt concentration stress,the main compatible solute accumulated by strain YZ1 was ectoine,and its content increased with increasing salt concentration.At the metabolic level,the increase in salt concentration reduces the intracellular carbon source material.The carbon source mainly flows to dimethylglycine,glycine,proline,etc,which maintains osmotic pressure balance.However,the content of L-aspartic acid,which is a precursor of ectoine that also regulates osmotic pressure,was significantly reduced.The extracellular viscous metabolites produced by strain YZ1 include proteins,sugars,lipids,alcohols,amines and other components.It is a complex extracellular polymer.At the same time,the strain YZ1 and its extracellular viscous metabolites have certain applications in environmental restoration and antioxidant activity:in terms of petroleum degradation,the strain YZ1 can grow using petroleum as the sole carbon source,and by 15 days,the degradation rate is about 40%.When adsorbing heavy metal ions,when the amount is 30 g/L,the adsorption rate for lead and cadmium ions can reach more than 90%,and the adsorption rate for zinc ions is more than 70%.In terms of antioxidant activity,extracellular viscous metabolites have a strong ability to scavenge ABTS free radicals.When the amount is 6 mg/mL,it can reach 100%;both DPPH and hydroxyl radicals have a certain degree of scavenging ability.When the addition amount is 10 mg/mL,the removal ability is 60%and 50%,respectively.The purpose of this study is to discover new species of halophilic bacteria and develop new types of natural active substances,research the metabolic mechanism of halophilic microorganisms under different salt concentration stresses and the application of their metabolites in environmental protection.