Papers by Keyword: Poly-β-Hydroxybutyrate

Abstract: Methanotrophs are aerobic microorganisms that utilize methane as substrates for growth and PHB Biosynthesis. Copper plays an important role in cell growth and PHB biosynthesis. The effect of initial copper concentration on cultivation of M. trichosporium IMV 3011 on methane was investigated. With the addition of 30μmol/L CuSO4•5H2O, PMMO activity improved to 4 times of that without copper addition. The highest density of cultivated cells is 0.48g dry wtL-1, which is 2 times of that without copper addition. The lag time shortened to 15.87h, and the growth rate increased to 0.082h-1.The PHB content increased to 8.3%. It is found that certain initial copper concentration is beneficial to expression of high particulate methane monooxygenase activity, which may contribute to the synthesis of PHB in the cell.

Abstract: A new fermentation strategy, one-step fermentation was developed for PHB production with high cell concentration and good productivity in a simplified way. Combined with the research results of PHB synthesis with the method of shake-flasks fermentation cultivation, the fermentation system was built based on the characteristics of fermentation tank cultivation,which was much superior to the traditional two-step fermentation. Based on shake flask studies, the full advantages of fermentation culture was taken to achieve the improvement of PHB production. Through this fermentation method with high PHB accumulation capacity, it provides a feasible way to expand the scale of PHB production, and promotes PHB industrial production process using Methane-Utilizing mixed Culture.

Abstract: The current status of biodegradable material PHB research was analyzed. The synthesis mechanism of PHB production by methane-oxidizing bacteria and effect factors of PHB yield were summarized. And progress direction about PHB polyester was forecasted, that provide theoretic base for studying PHB.

Abstract: Poly-3-hydroxybutyrate (PHB) has already become the hot spot research in food packaging area because of its excellent biocompatibility and biodegradability as a kind of new plastic substitute. The Methane-Utilizing mixed Culture HD6T is able to synthesize PHB with methane in an open system. In order to obtain microbial species of high production PHB low carbon cost in an open system, the ability of accumulating PHB was studied. Through inspecting the culture medium component, the results indicated that: Cultivation was performed in two stages: a continuous growth phase and a PHB accumulation phase under different concentration of essential nutrient (ammonium, nitrate, magnesium or copper) in batch culture. The highest density of cultivated cells was 0.72g dry wtL-1, and PHB content of biomass was as high as 31%.A bacterial mixed culture being used for the biotechnological production of PHB is an important step towards the development of a viable large-scale process for the production of PHB using cheap substrates like methane.content of biomass was as high as 31%.A bacterial mixed culture being used for the biotechnological production of PHB is an important step towards the development of a viable large-scale process for the production of PHB using cheap substrates like methane.

Abstract: Methane-utilizing mixed culture HD6T was successfully cultivated in a brief non-sterile process using methanol as a sole carbon and energy source for the production of poly-β-hydroxybutyrate(PHB). Shake-flask experiments showed HD6T could grow well in the mineral salt medium with the addition of methanol exposed to the air directly. This non-sterile process and the use of cheap substrates (methanol) can reduce the production costs of PHB. It was found that HD6T grew better and PHB production in a more effective way with an initial liquid methanol concentration of 0.15%(v/v).The lag phase duration, the maximum growth rate, the biomass concentration and the PHB yield, for the optimal conditions were, respectively, 12.03h, 0.04h-1(OD600), 1.54g/l(dry weight), 0.424g/l(dry weight). Methane-utilizing mixed culture HD6T appears to be a promising organism for PHB production.

Abstract: This paper focuses on an effective way to improve the thermostability of poly-β-hydroxybutyrate (PHB). Maleic anhydride (MA) is grafted onto PHB by 60Co γ of radiation. The spectra of both 1HNMR and 13CNMR were investigated following the radiation-induced polymerization. The results are consistent with successful grafting of the MA monomer onto the PHB, with a low graft degree. The graft degree and viscosity-average molecular weight Mηof the radiated samples were also investigated. The results observed through TGA demonstrate that thermostability has been measurably improved with the introduction of MA groups. These significant results suggest that wide commercial application of PHB may be possible.