Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, India.
Extremophiles. 2012 Jan;16(1):1-19. doi: 10.1007/s00792-011-0402-3. Epub 2011 Nov 13.
Acidophiles are ecologically and economically important group of microorganisms, which thrive in acidic natural (solfataric fields, sulfuric pools) as well as artificial man-made (areas associated with human activities such as mining of coal and metal ores) environments. They possess networked cellular adaptations to regulate pH inside the cell. Several extracellular enzymes from acidophiles are known to be functional at much lower pH than the cytoplasmic pH. Enzymes like amylases, proteases, ligases, cellulases, xylanases, α-glucosidases, endoglucanases, and esterases stable at low pH are known from various acidophilic microbes. The possibility of improving them by genetic engineering and directed evolution will further boost their industrial applications. Besides biocatalysts, other biomolecules such as plasmids, rusticynin, and maltose-binding protein have also been reported from acidophiles. Some strategies for circumventing the problems encountered in expressing genes encoding proteins from extreme acidophiles have been suggested. The investigations on the analysis of crystal structures of some acidophilic proteins have thrown light on their acid stability. Attempts are being made to use thermoacidophilic microbes for biofuel production from lignocellulosic biomass. The enzymes from acidophiles are mainly used in polymer degradation.
嗜酸微生物是一类在生态和经济上都非常重要的微生物，它们在酸性的自然环境（如沸腾泉、硫磺池）和人工环境（如与人类活动有关的区域，如采煤和金属矿石开采）中都能茁壮成长。它们具有网络状的细胞适应性，可调节细胞内的 pH 值。已知一些嗜酸微生物的细胞外酶在比细胞质 pH 值低得多的 pH 值下仍具有功能。一些在低 pH 值下稳定的酶，如淀粉酶、蛋白酶、连接酶、纤维素酶、木聚糖酶、α-葡萄糖苷酶、内切葡聚糖酶和酯酶，已从各种嗜酸微生物中被发现。通过遗传工程和定向进化来提高它们的性能，将进一步推动它们在工业上的应用。除了生物催化剂外，其他生物分子，如质粒、rusticyanin 和麦芽糖结合蛋白，也已从嗜酸微生物中被报道。已经提出了一些策略来解决从极端嗜酸微生物中表达编码蛋白质的基因时遇到的问题。对一些嗜酸蛋白晶体结构的分析研究揭示了它们的酸稳定性。目前正在尝试利用嗜热嗜酸微生物从木质纤维素生物质中生产生物燃料。嗜酸微生物的酶主要用于聚合物的降解。
