Collaborative Research: Engineering yeast consortia for surface-display of complex cellulosome structures: A consolidated bioprocessing approach from cellulosic biomass to ethanol

0903894中国的智慧价值建议的工程战略强调纤维素酶之间的水解效率和协同作用，而不是关注生产或使用的酶的数量。为了模仿纤维素高效降解的自然机制的成功，复杂的纤维素体(自组装的多酶复合体)将组装在酵母细胞表面，使产生乙醇的菌株能够利用纤维素并同时将其发酵成乙醇。更重要的是，通过将这些纤维素酶组织成有序结构，增强的协同作用将提高水解效率，从而提高乙醇产量。基于生物能量的限制，使用单一的酵母菌株进行表面锚定和纤维素酶分泌不太可能再次成功。为了解决这个问题，将开发一个合成酵母联合体，用于呈现复杂的纤维素体结构的功能。如果成功，这将允许大量的低成本农业残渣被用作生产乙醇的原材料。作物价值的提高会给农民带来额外的收入，更有效地利用土地，并有助于农业的长期可持续性。乙醇产量的增加减少了对环境的污染，减少了对进口石油的需求。代谢工程战略与过程技术的实施相结合是一项独特的努力，它将代谢工程的基本发展扩展为一种实用的补救技术。拟议的研究涉及分子遗传学、合成生物学和发酵的原理和方法的交叉。参与这项研究的研究生将对连接生物化学、现代遗传学和过程工程的重要接口和协同作用有一个综合的看法。由于研究和教育的整合是NSF的关键计划之一，拟议的研究将涉及K-12学校的学生、本科生和研究生，特别是来自代表性不足群体的参与。

0903894ChenIntellectual MeritThe engineering strategy proposed emphasizes the efficiency of hydrolysis and synergy among cellulases, rather than focusing on the amount of enzymes produced or used. To emulate the success of a natural mechanism for efficient cellulose hydrolysis, complex cellulosomes (self-assembled multi-enzyme complexes) will be assembled on the yeast cell surface, enabling the ethanol-producing strain to utilize cellulose and concomitantly ferment it to ethanol. More importantly, by organizing these cellulases in an ordered structure, the enhanced synergy will increase the efficiency in hydrolysis, and thereby enhance ethanol production. The use of a single yeast strain for surface anchoring and cellulase secretion is unlikely to be successful again based on bioenergetic limitations. To solve this problem, a synthetic yeast consortium will be developed for the functional presentation of the complex cellulosome structures.Broader ImpactsEngineering microbes to utilize cellulose eliminates the need for cellulose treatment. If successful, this will allow vastly abundant low-cost agriculture residues to be used as raw materials for ethanol production. The enhanced value of crops leads to additional incomes to farmers, more efficient land use, and contributes to long-term agriculture sustainability. The increased production of ethanol reduces pollution to the environment and the need for imported petroleum. The integration of metabolic engineering strategies with the implementation of process technology represents a unique effort that expands the fundamental development of metabolic engineering into a practical remediation technology. The proposed research involves intersection of principles and methods of molecular genetics, synthetic biology, and fermentation. Graduate students participating in this research will gain an integrated perspective of the important interfaces and synergies connecting biochemistry, modern genetics, and process engineering. As the integration of research and education is one of the key programs of NSF, the proposed research will involve the participation of K-12 school students, undergraduates and graduate students, particularly from underrepresented groups.