A Genome Scale Model of Geobacillus thermoglucosidasius (C56-YS93) reveals its biotechnological potential on rice straw hydrolysate
A Genome Scale Model of Geobacillus thermoglucosidasius (C56-YS93) reveals its biotechnological potential on rice straw hydrolysate
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DOI：
10.1016/j.jbiotec.2017.03.031
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发表时间：
2017-06-10
影响因子：
4.1
通讯作者：
Srivastava, Shireesh
中科院分区：
文献类型：
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作者：
Ahmad, Ahmad;Hartman, Hassan B.;Srivastava, Shireesh
稻草是一种主要的农作物残渣，在许多国家都被焚烧，造成严重的空气污染。因此，处理稻草的替代途径是必要的。对稻草水解液进行生物技术处理，有可能将这些农业废弃物转化为有价值的生物燃料(S)和平台化学品。热葡萄糖苷地质杆菌是一种嗜热菌，其性质特别适合作为木质纤维生物过程的生物催化剂，如高最适温度和对高水平乙醇的耐受性。然而，热葡萄糖菌利用稻草水解液中的糖生产生物乙醇和其他平台化学品的能力还没有得到充分的探索。在这项工作中，我们创建了一个包含736个基因产物、1159个反应和1163个代谢物的生物体的基因组规模代谢模型(记为iGT736)。该模型通过纯理论方法和通过将模型的行为与先前发表的实验结果进行比较来验证。然后，该模型被用于确定葡萄糖和木糖-稻草水解液中的两种主要糖-的各种平台化学品的产率。与大肠杆菌模型的结果比较表明，热葡萄糖苷杆菌能够产生更广泛的产物，而同样由大肠杆菌产生的产物，产量是可比的。我们还讨论了利用稻草水解液中的一种次要成分阿拉伯糖的策略，并提出了一些额外的反应来合成木糖醇，而木糖醇目前还不是由G。我们的结果为目前探索热葡萄糖苷杆菌的工业潜力提供了额外的动力，我们将我们的模型公之于众，以帮助开发这种生物的代谢工程策略。
Rice straw is a major crop residue which is burnt in many countries, creating significant air pollution. Thus, alternative routes for disposal of rice straw are needed. Biotechnological treatment of rice straw hydrolysate has potential to convert this agriculture waste into valuable biofuel(s) and platform chemicals. Geobacillus thermoglucosidasius is a thermophile with properties specially suited for use as a biocatalyst in lignocellulosic bioprocesses, such as high optimal temperature and tolerance to high levels of ethanol. However, the capabilities of G. thermoglucosidasius to utilise sugars in rice straw hydrolysate for making bioethanol and other platform chemicals have not been fully explored. In this work, we have created a genome scale metabolic model (denoted iGT736) of the organism containing 736 gene products, 1159 reactions and 1163 metabolites. The model was validated both by purely theoretical approaches and by comparing the behaviour of the model to previously published experimental results. The model was then used to determine the yields of a variety of platform chemicals from glucose and xylose - two primary sugars in rice straw hydrolysate. A comparison with results from a model of Escherichia coli shows that G. thermoglucosidasius is capable of producing a wider range of products, and that for the products also produced by E. coli, the yields are comparable. We also discuss strategies to utilise arabinose, a minor component of rice straw hydrolysate, and propose additional reactions to lead to the synthesis of xylitol, not currently produced by G. thermoglucosidasius. Our results provide additional motivation for the current exploration of the industrial potential of G. thermoglucosidasius and we make our model publicly available to aid the development of metabolic engineering strategies for this organism.