Luan Guodong, Dong Hongjun, Zhang Tianrui, Lin Zhao, Zhang Yanping, Li Yin, Cai Zhen
CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
J Biotechnol. 2014 May 20;178:38-40. doi: 10.1016/j.jbiotec.2014.03.010. Epub 2014 Mar 15.
The cellular robustness is a big concern for efficient microbial production of biofuels and biochemicals. In this study, the groESL genes from extremophilic bacteria were found to serve as transplantable stress-response elements to improve diverse types of stress-tolerances of other microbes. By overexpressing the groESL from the solvent-tolerant Pseudomonas putida in Escherichia coli, its thermo-tolerance and ethanol-tolerance were significantly increased. Meanwhile, the groESL from the thermophilic Thermoanaerobacter tengcongensis endowed Clostridium acetobutylicum with improved corn cob hydrolysates (CCH)-tolerance as well as elevated butanol productivity. The chaperonins GroESL have been widely considered as cellular stress-response proteins and overexpression of native groESL has been proven to improve cellular tolerances facing various stresses. Here we found that the groESL genes from extremophilic bacteria were superior to the native ones, possibly because they have adapted to the environmental stresses during long-term natural evolution. Moreover, our results also revealed that different extreme groESL genes performed quite different in different microbes. Thus the relation and compatibility between the extremophiles and the host must be considered for selection of the proper groESL for engineering microbial robustness.
细胞稳健性是微生物高效生产生物燃料和生物化学品的一个重大问题。在本研究中，发现来自嗜极细菌的groESL基因可作为可移植的应激反应元件，以提高其他微生物的多种应激耐受性。通过在大肠杆菌中过表达来自耐溶剂恶臭假单胞菌的groESL，其耐热性和耐乙醇性显著提高。同时，来自嗜热嗜热栖热菌的groESL赋予丙酮丁醇梭菌更高的玉米芯水解产物（CCH）耐受性以及提高的丁醇生产率。伴侣蛋白GroESL已被广泛认为是细胞应激反应蛋白，并且已证明过表达天然groESL可提高细胞面对各种应激的耐受性。在这里，我们发现来自嗜极细菌的groESL基因优于天然基因，这可能是因为它们在长期自然进化过程中适应了环境压力。此外，我们的结果还表明，不同的极端groESL基因在不同的微生物中表现差异很大。因此，在选择合适的groESL来构建微生物稳健性时，必须考虑嗜极菌与宿主之间的关系和兼容性。
