常温土壤中耐冷菌的分离、鉴定及产酶分析

目的:从常温土壤中筛选冷适应微生物,并进行初步鉴定和产低温酶分析。方法:采集吉首大学校园内土壤样品,通过低温富集培养筛选冷适应微生物;通过形态观察、生理生化特性检测和基于16S rRNA基因序列的系统发育分析,对分离的菌株进行初步鉴定;利用平板筛选法检测其产低温酶特性。结果:分离获得6株耐冷细菌JSBP-1～JSBP-6,初步鉴定其分属假单胞菌属(Pseudomonas)、紫色杆菌属(Janthinobacterium)和节杆菌属(Arthrobacter);在5℃和15℃培养条件下,菌株JSBP-1产蛋白酶能力较强,JSBP-2和JSBP-6产淀粉酶能力较强,JSBP-5仅在5℃条件下有较强的产脂肪酶特性。结论:常温土壤中存在一定数量的冷适应微生物,其中假单胞菌是其优势菌群之一。这类适冷微生物菌群具有潜在的生产低温酶能力。

Isolation and Identification of Psychrotrophic Bacteria in Normal Temperature Soils and Their Properties of Cold-Adapted Enzymes Production

Objective： To screen cold-adapted microorganisms from normal temperature soils,and identify the isolated strains preliminarily and assay their cold-active enzyme production.Methods： Cold-adapted microorganisms were isolated from normal temperature soils at the campus of Jishou university by enrichment culture at 2℃.The isolated strains were identified by bacterial morphological,physiological and biochemical characteristics,and using phylogenetic relationships based on 16S rRNA gene sequences.The cold-adapted enzyme production of these bacteria was analyzed by substrate hydrolysis experiments.Results： Six strains of psychrotrophic bacteria,named after JSBP-1～JSBP-6,were isolated from the normal temperature soil samples,and identified as Pseudomonas sp.,Janthinobacterium sp.and Arthrobacter sp.respectively by morphological,physiological and biochemical characteristics,and the phylogenetic analysis of 16S rRNA gene.JSBP-1 had the capability of producing more cold-adapted protease,JSBP-2 and JSBP-6 had the capability of producing more cold-adapted amylase at 5℃ and 15℃ respectively,and JSBP-5 could produce more cold-active lipase only at 5℃.Conclusion： There are a certain amount of cold-adapted microorganisms in normal temperature soils,of which Pseudomonas sp.is one of predominant populations.These microorganisms are potential resources of producing cold-adapted enzymes.