可培养盐碱菌多样性的研究进展

存在于高盐强碱极端环境的微生物因其独特的生命方式,引起了广泛的关注。根据盐碱环境所含的可溶性盐成分,可分为"NaCl型"和"苏打型(Na_2CO_3/NaHCO_3)"两大类,前者的碱性pH值较低而后者碱性pH值较高。本文总结了盐碱菌适宜生长条件在盐度0.5 mol/L和碱性pH 9.0之上且有效发表的标准菌株,并对这些菌株的生物多样性及生理特性进行了阐述;可培养盐碱细菌的数量及其多样性远远大于盐碱古菌,但是盐碱细菌对高盐度和强碱性p H依赖程度相对较低。盐碱细菌主要组成依次为芽孢杆菌纲(Bacilli,占总数约40%)、γ-变形菌纲(γ-Proteobacteria,30%)、梭菌纲(Clostridia,11%)、δ-变形菌纲(δ-Proteobacteria,6%)和放线菌纲(Actinobacteria,6%),而盐碱古菌主要组成为盐古菌纲(Halobacteria,92%)和甲烷微菌纲(Methanomicrobia,8%)。这些极端微生物在生物地球化学过程中或生态循环中扮演着重要的角色和功能,挖掘和利用盐碱菌具有重要意义。

Biodiversity of culture-dependent haloalkaliphilic microorganisms

Microorganisms growing at high salinity and elevated alkaline environments have gained wide attention in term of their unique properties. According to the soluble composition, saline-alkaline environment can be two groups, i.e. "NaCl type" and "soda type (Na₂CO₃/NaHCO₃)". The alkaline pH of the former is relatively low, and that of the latter is higher. This review summarizes validated haloalkaliphilic type strains for optimal growth requiring Na⁺ concentrations above 0.5 mol/L and an alkaline pH of 9, and their biodiversity and physiological characteristics. The biodiversity of the halophilic bacteria is far greater than that of halophilic archaea. Halophilic bacteria are mainly composed of Bacilli (40% of the total), gamma-Proteobacteria (30%), Clostridia (11%), delta-Proteobacteria (6%) and Actinobacteria (6%); Halophilic archaea are Halobacteria (92%) and Methanomicrobia (8%). These extremophiles under double stress play essential roles and functions in biogeochemical processes and the ecological function.