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Isolation of a Novel Pseudomonas Species SP2 Producing Vitamin B12 under Aerobic Condition
Mariadhas Valan Arasu,Ritam Sarkar,Balaji Sundara Sekar,Vinod Kumar,Chelladurai Rathnasingh,Jin-dal-rae Choi,Hyohak Song,Doyoung Seung,박성훈 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.1
Vitamin B12 is a complex biomolecule that acts as a cofactor for a variety of enzymes in microbial metabolism. Pseudomonas denitrificans is exclusively used as an industrial strain for the production of vitamin B12under aerobic conditions. However, only a few strains of Pseudomonas have been reported to possess the capability of producing this vitamin and they are strongly patentprotected. To improve the applicability of the vitamin B12-producing microorganisms, a new isolate was obtained from municipal waste samples and characterized for its biological properties. The new isolate, designated as SP2,was identified to be a Pseudomonas species based on the sequence homology of its 16S rDNA. Pseudomonas species SP2 had essential genes for vitamin B12 synthesis such as cobB and cobQ and produced a similar amount of vitamin B12 (10.6 ± 0.05 μg/mL) as P. denitrificans ATCC 13867 in 24 h flask culture. SP2 grew well under aerobic condition with the maximum specific growth rate (μmax) of 0.91 +0.03/h, but showed a poor growth under micro-aerobic conditions. SP2 was resistant to antibiotics like streptomycin,carbenicillin, ampicillin, cefpodoxime, colistin, nalidixic acid and sparfloxacin. The ability of SP2 to grow faster and produce vitamin B12 under aerobic conditions makes it a promising host for the production of some biochemicals requiring a coenzyme B12-dependent enzyme, such as glycerol dehydratase.
Kumar, Vinod,Sankaranarayanan, Mugesh,Jae, Kyeung-eun,Durgapal, Meetu,Ashok, Somasundar,Ko, Yeounjoo,Sarkar, Ritam,Park, Sunghoon Springer-Verlag 2012 Applied microbiology and biotechnology Vol.96 No.2
<P>The co-production of 3-hydroxypropionic acid (3HP) and 1,3-propanediol (PDO) from glycerol was studied using the resting cells of a recombinant Klebsiella pneumoniae J2B strain that overexpresses an aldehyde dehydrogenase (KGSADH). Active biomass was produced in a mineral salt medium containing yeast extract and glycerol under a range of aeration conditions, and shifted to potassium phosphate buffer containing glycerol for bioconversion. The microaerobic or anaerobic conditions were favorable for both the production of active biomass and subsequent bioconversion. At the flask level, the recombinant strain (2.0?g?CDW/L) grown under microaerobic conditions produced 43.2?mM 3HP and 59.0?mM PDO from glycerol (117?mM) in 30?min with a cumulative yield of 0.87?(mol/mol). The fed-batch bioconversion, which was performed in a 1.5-L bioreactor with 1.0?g?CDW/L at a constant pH?7.0 under anaerobic conditions, resulted in 125.6?mM 3HP and 209.5?mM PDO in 12?h with a cumulative overall productivity, yield, and maximum specific production rate of 27.9?mmol/L/h, 0.71 (mol/mol), and 128.5?mmol/g CDW/h, respectively. Lactate, succinate and 2,3-butanediol were the major by-products, whereas the production of acetate and ethanol was marginal. This is the first report of the simultaneous production of 3HP and PDO from glycerol using a resting cell system.</P>