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Engineering the filamentous fungus Neurospora crassa for lipid production from lignocellulosic biomass
Author(s) -
Roche Christine M.,
Glass N. Louise,
Blanch Harvey W.,
Clark Douglas S.
Publication year - 2014
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25211
Subject(s) - neurospora crassa , biochemistry , fatty acid , catabolite repression , biosynthesis , cellulose , metabolic engineering , biology , strain (injury) , chemistry , food science , mutant , enzyme , gene , anatomy
Microbially produced triacylglycerol (TAG) is a potential feedstock for the production of biodiesel, but its commercialization will require high yields from low‐cost renewable feedstocks such as lignocellulose. The present study employs a multi‐gene approach to increasing TAG biosynthesis in the filamentous fungus Neurospora crassa . We demonstrate the redirection of carbon flux from glycogen biosynthesis towards fatty acid biosynthesis in a glycogen synthase deletion strain (Δ gsy‐1 ). Furthermore, combining Δ gsy‐1 with an enhanced TAG biosynthetic strain (acyl‐Coenzyme A synthase; Δ acs‐3 ) of N. crassa yielded a twofold increase in total fatty acid accumulation over the control strain. The cellulose degrading potential of this double deletion strain was improved by deleting of the carbon catabolite regulation transcription factor (Δ cre‐1 ) to create the triple deletion strain Δ acs‐3 Δ cre‐1 ; Δ gsy‐1 . This strain exhibited early and increased cellulase expression, as well as fourfold increased total fatty acid accumulation over the control on inhibitor‐free model cellulose medium. The Δ cre‐1 mutation, however, was not beneficial for total fatty acid accumulation from pretreated lignocellulose. Conversion of dilute‐acid pretreated Miscanthus to TAG was maximum in the constructed strain Δ acs‐3 ; Δ gsy‐1 , which accumulated 2.3‐fold more total fatty acid than the wild‐type control strain, corresponding to a total fatty acid yield of 37.9 mg/g dry untreated Miscanthus . Biotechnol. Bioeng. 2014;111: 1097–1107. © 2014 Wiley Periodicals, Inc.