Location: Crops Pathology and Genetics ResearchTitle: Engineering Neurospora crassa for improved cellobiose and cellobionate production
|HILDEBRAND, AMANDA - University Of California|
|SZEWCZYK, EDYTA - University Of California|
|LIN, HUI - University Of California|
|FAN, ZHILIANG - University Of California|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2014
Publication Date: 1/15/2015
Publication URL: http://aem.asm.org/content/81/2/597.full.pdf+html?sid=6333baa2-48ad-4db4-b5d6-cb2a45eb0
Citation: Hildebrand, A., Szewczyk, E., Lin, H., Kasuga, T., Fan, Z. 2015. Engineering Neurospora crassa for improved cellobiose and cellobionate production. Applied and Environmental Microbiology. 81:597-603.
Technical Abstract: We report engineering Neurospora crassa to improve the yield of cellobiose and cellobionate from cellulose. A previously engineered strain of N. crassa (F5) with six out of seven bgl genes knocked out was shown to produce cellobiose and cellobionate directly from cellulose without the addition of exogenous cellulases. In this study, the F5 strain was further modified to improve the yield of cellobiose and cellobionate from cellulose by increasing cellulase production and decreasing product consumption. The effects of two catabolite repression genes cre-1 and ace-1 on cellulase production were investigated. The F5'ace-1 mutant showed no improvement over the wild type. The F5'cre-1 and F5'ace-1'cre-1 strains showed improved cellobiose dehydrogenase and exoglucanase expression. However, this improvement in cellulase expression did not lead to an improvement in cellobiose or cellobionate production. The cellobionate phosphorylase gene (ndvB) was deleted from the genome of F5'ace-1'cre-1 to prevent theconsumption of cellobiose and cellobionate. Despite a slightly reduced hydrolysis rate, the F5'ace-1'cre-1'ndvB strain converted 79% of the cellulose consumed to the desired products, cellobiose and cellobionate, as compared to 19% by the strain F5'ace-1'cre-1.