Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6494390 | Metabolic Engineering | 2015 | 37 Pages |
Abstract
Klebsiella oxytoca KMS005 (âadhEâackA-ptaâldhA) was metabolically engineered to improve 2,3-butanediol (BDO) yield. Elimination of alcohol dehydrogenase E (adhE), acetate kinase A-phosphotransacetylase (ackA-pta), and lactate dehydrogenase A (ldhA) enzymes allowed BDO production as a primary pathway for NADH re-oxidation, and significantly reduced by-products. KMS005 was screened for the efficient glucose utilization by metabolic evolution. KMS005-73T improved BDO production at a concentration of 23.5±0.5 g/L with yield of 0.46±0.02 g/g in mineral salts medium containing 50 g/L glucose in a shake flask. KMS005-73T also exhibited BDO yields of about 0.40-0.42 g/g from sugarcane molasses, cassava starch, and maltodextrin. During fed-batch fermentation, KMS005-73T produced BDO at a concentration, yield, and overall and specific productivities of 117.4±4.5 g/L, 0.49±0.02 g/g, 1.20±0.05 g/L h, and 27.2±1.1 g/gCDW, respectively. No acetoin, lactate, and formate were detected, and only trace amounts of acetate and ethanol were formed. The strain also produced the least by-products and the highest BDO yield among other Klebsiella strains previously developed.
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Authors
Kaemwich Jantama, Pattharasedthi Polyiam, Panwana Khunnonkwao, Sitha Chan, Maytawadee Sangproo, Kirin Khor, Sirima Suvarnakuta Jantama, Sunthorn Kanchanatawee,