Molecular insights into transcriptional regulation for the optimisation of butanol-producing clostridia.

在世纪早期，丙酮和丁醇的工业生产依赖于由梭菌属的产溶剂成员进行的大规模微生物发酵。如今，这种经典的“AB发酵”工艺在经济上不再可行。因此，重要的是通过代谢工程来改善生物体的性能，旨在增加丁醇滴度、产率和生产率。然而，要通过这一途径建立生物燃料和化学品的可持续生产，尚未取得决定性的突破。丙酮丁醇梭菌菌株对基因工程特别感兴趣，但需要更好地理解生物体的生理学，特别是控制溶剂形成的时间和程度的机制。细菌通讯机制在丁醇和丙酮的形成中起着至关重要的作用，RRNPP家族的新型转录调节因子已被鉴定为该系统的重要组成部分。本项目的总体目标是研究转录调节因子作用模式的分子基础，以便利用结构生物学、蛋白质工程、生物化学、微生物学和基因工程技术来工程化高性能丁醇生产菌株。这种调节剂的失活几乎完全消除了丙酮和丁醇的形成。当细胞活跃生长时，该蛋白似乎是无活性的，但当细菌进入稳定期并开始产生溶剂时，该蛋白呈现活性状态。对潜在的分子机制的详细理解将极大地促进改进的溶剂产生菌株的成功工程化。此外，由于该调节剂的同系物也存在于梭菌属的所有物种中，包括其致病成员，因此还将获得对引起腹泻、破伤风和肉毒杆菌中毒的生物体如何运作的新见解。

In the early 20th century, industrial production of acetone and butanol relied on large scale microbial fermentations carried out by solvent producing members of the genus Clostridium. Today this classical 'AB fermentation' process is no longer economically viable. Thus, it is important to improve the organisms' performance through metabolic engineering, aiming at increasing butanol titres, yields and productivity. However, decisive breakthroughs are yet to be made in order to establish a sustainable production of biofuels and chemicals through this route. The strain Clostridium acetobutylicum is of particular interest for genetic engineering, but a better understanding of the organisms' physiology, in particular the mechanisms that govern timing and extent of solvent formation is required. Bacterial communication mechanisms play a crucial role in butanol and acetone formation and novel transcriptional regulators of the RRNPP family have been identified as being an important part of this system. The overall objective of this project is to investigate the molecular basis of the transcriptional regulator's mode of action in order to engineer high performance butanol producing strains using structural biology, protein engineering, biochemistry, microbiology and genetic engineering techniques. Inactivation of this regulator almost completely abolishes the formation of both acetone and butanol. The protein appears to be inactive when cells are actively growing but adopts an active state when the bacteria enter stationary phase and begin to produce solvents. A detailed understanding of the underlying molecular mechanism will greatly facilitate successful engineering of improved solvent producing strains. In addition, as homologues of this regulator are also present in all species of the genus Clostridium, including its pathogenic members, novel insights into how organisms operate that cause diarrhoea, tetanus and botulism will also be gained.