摘要: |
With the advent of directed molecular evolution techniques, a whole new potential for enzyme engineering (instead of microbial engineering) and improvement has opened. The greatest advantage of directed evolution is that it is independent of knowledge of enzyme structure and of the interactions between enzyme and substrate. Recently, the project has developed a novel hydrogel (termed P-gel) which can efficiently produce proteins without any living cells. The unique advantage of the P-gel system is that it is totally cell-free, thus it is ideally suited to express a consortium of proteins without worrying about the toxic effect to or low-yield problems in living cells. Enzymatic conversion of natural cellulose, in particular, non-food cellulose, to bioethanol will have great impact on alternative and renewable energy development, local economy, and environment protection. However, economical production of bioethanol from cellulosic biomass is currently impeded by the high cost and low efficiency of cellulase complexes. Three goals for this project: 1) Using P-gel to establish cellulase mutant selection methods based on insoluble substrates; 2) Using microfluidics to generate P-gel microdroplets in order to establish a high-throughput method for screening the high activity cellulase mutants; and 3) Highthroughput molecular engineering of cellulase consortia. The project will combine the molecular evolution approach with our cell-free P-gel and engineer cellulase consortia in a high-throughput fashion via the microfluidic format. The project expects that it will establish a robust, P-gelbased, high-throughput protein engineering platform that is able to molecularly evolve not just single proteins, but also protein consortia. The project also expects to achieve a five- to ten-fold reduction in the cost of cellulase enzymes by dramatically improving the efficiency of these enzymes. |