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Reilly MC, Kim J, Lynn J, Simmons BA, Gladden JM, Magnuson JK, Baker SE. Forward genetics screen coupled with whole-genome resequencing identifies novel gene targets for improving heterologous enzyme production in Aspergillus niger. Appl Microbiol Biotechnol 2018; 102:1797-1807. [PMID: 29305699 PMCID: PMC5794824 DOI: 10.1007/s00253-017-8717-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 12/12/2022]
Abstract
Plant biomass, once reduced to its composite sugars, can be converted to fuel substitutes. One means of overcoming the recalcitrance of lignocellulose is pretreatment followed by enzymatic hydrolysis. However, currently available commercial enzyme cocktails are inhibited in the presence of residual pretreatment chemicals. Recent studies have identified a number of cellulolytic enzymes from bacteria that are tolerant to pretreatment chemicals such as ionic liquids. The challenge now is generation of these enzymes in copious amounts, an arena where fungal organisms such as Aspergillus niger have proven efficient. Fungal host strains still need to be engineered to increase production titers of heterologous protein over native enzymes, which has been a difficult task. Here, we developed a forward genetics screen coupled with whole-genome resequencing to identify specific lesions responsible for a protein hyper-production phenotype in A. niger. This strategy successfully identified novel targets, including a low-affinity glucose transporter, MstC, whose deletion significantly improved secretion of recombinant proteins driven by a glucoamylase promoter.
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Affiliation(s)
- Morgann C Reilly
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Chemical and Biological Processes Development Group, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Joonhoon Kim
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Chemical and Biological Processes Development Group, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Jed Lynn
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Naval Medical Research Unit Dayton, Wright-Patterson Air Force Base, Dayton, OH, 45433, USA
| | - Blake A Simmons
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John M Gladden
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biomass Science and Conversion Technologies Department, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Jon K Magnuson
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Chemical and Biological Processes Development Group, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Scott E Baker
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA. .,Biosystems Design and Simulation Group, Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
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