title: High Production of 2,3-butanediol by a Mutant Strain of the Newly IsolatedKlebsiella pneumoniaeSRP2 with Increased Tolerance Towards Glycerol.
abstract: Biodiesel, a renewable fuel produced by transesterification of animal fats and vegetable oils, generates about 10% (v/v) of crude glycerol as a core byproduct. The high volume of this non bio-degradable glycerol is becoming of a great environmental and economical concern due to its worldwide ever-growing surplus. Herein we report a high production of 2,3-butanediol (2,3-BD) from pure and biodiesel derived crude glycerol using a mutantK. pneumoniaeSRM2 obtained from a newly isolated strainKlebsiella pneumoniaeSRP2. The mutant strain SRM2 with standing high glycerol concentration (220 g L-1of medium) could rapidly convert glycerol aerobically to 2,3-BD, a versatile product extensively used in chemical, pharmaceutical and fuel industries Our study revealed that an increased GDH activity led to a substantially enhanced production of 2,3-BD. The mutant strain exhibited 1.3-fold higher activity of GDH than that of parent strain (500.08 vs. 638.6 µmol min-1mg-1protein), yielding of 32.3 g L-1and 77.5 g L-12,3-BD with glycerol in batch and fed-batch process respectively. However, in batch culture with crude glycerol, cell growth and glycerol consumption were expressively boosted, and 2,3-BD production was 27.7 g L-1from 75.0 g/L crude glycerol. In this report, the optimal conditions for high production of 2,3-BD were defined in a completely aerobic process, and 0.59 g g-1product yield of 2,3-BD was attained by the mutated strainK. pneumoniaeSRM2, which is the highest amount obtained from batch biotransformation process of glycerol metabolism till today. These results indicated that our newly developed mutant can tolerate high concentration of glycerol, have a high glycerol utilization rate, and high product yield of 2,3-BD. It is demonstrated that the mutant strainK. pneumoniaeSRM2 has an ability to produce fewer co-products at trace concentrations at higher glycerol concentrations, and could be a potential candidate for 2,3-DB production in an industrial bioconversion process.
authors.affiliation: Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada;; Department of Microbiology, University of Chittagong, Bangladesh.
authors.forename: Md Shafiqur
authors.initials: MS
authors.lastname: Rahman
authors.affiliation: Institute for Chemicals and Fuels from Alternative Resources (ICFAR), Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Chunbao Charles
authors.initials: CC
authors.lastname: Xu
authors.affiliation: Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Kesen
authors.initials: K
authors.lastname: Ma
authors.affiliation: Institute for Chemicals and Fuels from Alternative Resources (ICFAR), Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Malaya
authors.initials: M
authors.lastname: Nanda
authors.affiliation: Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Qin
mesh_terms: D061249:Batch Cell Culture Techniques; D002072:Butylene Glycols / Q000378:metabolism*; D005990:Glycerol / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000472:pathogenicity*; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism
chemical_list: D002072:Butylene Glycols; C026978:2,3-butylene glycol; D013401:Sugar Alcohol Dehydrogenases; C020672:glycerol dehydrogenase; D005990:Glycerol
keywords: 2; 3-Butanediol; Bioconversion; Crude glycerol; Glycerol dehydrogenase; Klebsiella pneumoniae.