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A new bacterial strain, isolated from groundwater contaminated with explosives, was characterized as a pink-pigmented facultative methylotroph, affiliated to the genus Methylobacterium. The bacterial isolate designated as strain GW2 was found capable of producing the homopolymer poly-3-hydroxybutyrate (PHB) from various carbon sources such as methanol, ethanol, and succinate. Methanol acted as the best substrate for the production of PHB reaching 40 % w/w dry biomass. PHB accumulation was observed to be a growth-associated process, so that there was no need for two-step fermentation. Optimal growth occurred at 0.5 % (v/v) methanol concentration, and growth was strongly inhibited at alpha concentration above 2 % (v/v). Methylobacterium sp. strain GW2 was also able to accumulate the copolyester poly-3-hydroxybutyrate-poly-3-hydroxyvalerate (PHB/HV) when valeric acid was supplied as an auxiliary carbon source to methanol. After 66 h, a copolymer content of 30 % (w/w) was achieved with a PHB to PHV ratio of 1:2. Biopolymers produced by strain GW2 had an average molecular weight ranging from 229,350 to 233,050 Da for homopolymer PHB and from 362,430 to 411,300 Da for the copolymer PHB/HV.

Bacillus thuringiensis subsp kurstaki was grown in batch and fed batch cultures using wastewater sludge as a raw material. A simple fed batch strategy based on dissolved oxygen measurement during the fermentation cycle was developed in this work. It was established that while shifting the process strategy from batch to fed batch, the maximum spore concentration was increased from 5.62 × 10 8 to 8.6 × 10 8 colony forming units per cm 3 and resulted in an increase of entomocidal activity from 13 × 10 9 to 18 × 10 9 spruce budworm potency units per dm 3 . Higher entomotoxicity was recorded at low spore concentration using wastewater sludge as a raw material whereas low entomotoxicity was reported at high spore concentration in synthetic medium.

/npsi/ctrl?action=rtdoc&an=3539342&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=3539342&lang=frAccess and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur.Applied Microbiology and Biotechnology, 77, 2, Production of Poly-β-Hydroxybutyrate ( Abstract Maple sap, an abundant natural product especially in Canada, is rich in sucrose and thus may represent an ideal renewable feedstock for the production of a wide variety of value-added products. In the present study, maple sap or sucrose was employed as a carbon source to Alcaligenes latus for the production of poly-β-hydroxybutyrate (PHB). In shake flasks, the biomass obtained from both the sap and sucrose were 4.4±0.5 and 2.9±0.3 g/L, and the PHB contents were 77.6±1.5 and 74.1±2.0%, respectively. Subsequent batch fermentation (10 L sap) resulted in the formation of 4.2±0.3 g/L biomass and a PHB content of 77.0±2.6%. The number average molecular weights of the PHB produced by A. latus from maple sap and pure sucrose media were 300±66×10 3 and 313±104×10 3 g/mol, respectively. Near-infrared, 1 H magnetic resonance imaging (MRI), and 13 C-MRI spectra of the microbially produced PHB completely matched those obtained with a reference material of poly[(R)-3-hydroxybutyric acid]. The polymer was found to be optically active with [α] 25 D equaled to −7.87 in chloroform. The melting point (177.0°C) and enthalpy of fusion (77.2 J/g) of the polymer were also in line with those reported, i.e., 177°C and 81 J/g, respectively.