Resolving the formidable barrier of oxygen transferring rate (OTR) in ultrahigh-titer bioconversion/biocatalysis by a sealed-oxygen supply biotechnology (SOS)
Resolving the formidable barrier of oxygen transferring rate (OTR) in ultrahigh-titer bioconversion/biocatalysis by a sealed-oxygen supply biotechnology (SOS)
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DOI：
10.1186/s13068-019-1642-1
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发表时间：
2020-01-04
影响因子：
6.3
通讯作者：
Xu, Yong
中科院分区：
文献类型：
--
作者：
Hua, Xia;Zhou, Xin;Xu, Yong
生物工程与化学工程竞争的关键问题是产品效价和体积产率。最直接和有效的方法通常是采用高密度生物催化剂，而超高密度生物催化剂负载和底物/产物滴度会导致传质减弱和诱发泡沫问题。在高密度专性好氧生物转化中，氧气作为电子受体是生物过程中的限速步骤，但充足的氧气供应将导致发泡，从而导致氧气利用率和额外消泡剂的使用显著减少。在本研究中，我们设计了一种新型的密封供氧（SOS）生物技术，以解决生物基燃料和化工生产过程中氧气传输速率（OTR）的巨大障碍。结果在系统分析氧葡萄糖杆菌全细胞催化作用的基础上，设计了一种新型的密闭供氧技术，并进行了醇类、糖类等生物催化氧化实验。在SOS密封搅拌槽生物反应器中，通过简单的自动在线供氧操作技巧，轻松解决了OTR阻隔和发泡问题。我们最终得到了木酸（XA）、3-羟基丙酸（3-HPA）和赤藓糖的超高滴度产物，分别为588.4 g/L、69.4 g/L和364.7 g/L。此外，与常规生物技术相比，三种化工产品的体积生产率提高了150-250%。这种SOS技术提供了一种很有前途的方法来提高生物工程的竞争力和优于化学工程的优势。结论SOS技术是一种经济、普遍适用的全细胞催化生产生物基燃料和化学品的方法。这项新技术极大地提升了生物工程相对于化学工程的竞争力，为生物燃料的绿色环保利用提供了一个有前景的平台。
Background The critical issue in the competitiveness between bioengineering and chemical engineering is the products titer and the volume productivity. The most direct and effective approach usually employs high-density biocatalyst, while the weakened mass transfer and evoked foam problem accompany ultrahigh-density biocatalyst loading and substrate/product titer. In high-density obligate aerobic bioconversion, oxygen as electron acceptor is a speed-limiting step in bioprocesses, but sufficient oxygen supply will lead to the foaming which results in a significant reduction in oxygen utilization and the use of additional defoamers. In this study, we designed a novel sealed-oxygen supply (SOS) biotechnology to resolve the formidable barrier of oxygen transferring rate (OTR), for bio-based fuels and chemical production process. Results Based on systemic analysis of whole-cell catalysis in Gluconobacter oxydans, a novel sealed-oxygen supply technology was smartly designed and experimentally performed for biocatalytic oxidation of alcohols, sugars and so on. By a simple operation skill of automatic online supply of oxygen in a sealed stirring tank bioreactor of SOS, OTR barrier and foaming problem was resolved with great ease. We finally obtained ultrahigh-titer products of xylonic acid (XA), 3-hydroxypropionic acid (3-HPA), and erythrulose at 588.4 g/L, 69.4 g/L, and 364.7 g/L, respectively. Moreover, the volume productivity of three chemical products was improved by 150-250% compared with normal biotechnology. This SOS technology provides a promising approach to promote bioengineering competitiveness and advantages over chemical engineering. Conclusion SOS technology was demonstrated as an economic and universally applicable approach to bio-based fuels and chemicals production by whole-cell catalysis. The novel technology greatly promotes the competitiveness of bioengineering for chemical engineering, and provides a promising platform for the green and environmental use of biofuels.