Production of PHB by a Bacillus megaterium strain using sugarcane molasses and corn steep liquor as sole carbon and nitrogen source

Faculty of Science, Alexandria University, Al Iskandarīyah, Alexandria, Egypt
Microbiological Research (Impact Factor: 2.56). 02/2001; 156(3):201-7. DOI: 10.1078/0944-5013-00104
Source: PubMed


Poly(hydroxybutyric acid) (PHB) and other biodegradable polyesters are promising candidates for the development of environment-friendly, totally biodegradable plastics. The use of cane molasses and corn steep liquor, two of the cheapest substrates available in Egypt, may help to reduce the cost of producing such biopolyesters. In this work, the effect of different carbon sources was studied. Maximum production of PHB was obtained with cane molasses and glucose as sole carbon sources (40.8, 39.9 per mg cell dry matter, respectively). The best growth was obtained with 3% molasses, while maximum yield of PHB (46.2% per mg cell dry matter) was obtained with 2% molasses. Corn steep liquor was the best nitrogen source for PHB synthesis (32.7 mg per cell dry matter), on the other hand, best growth was observed when ammonium chloride, ammonium sulphate, ammonium oxalate or ammonium phosphate were used as nitrogen sources.

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    • "Author reported, that even 2.5 g/L of P(3HB) can be synthesized by A. vinelandii UWD on a beet molasses-based medium. Accordingly to Gouda et al. (2001) B. megaterium is able to accumulate up to 46.2% of P(3HB) when 3% (w/v) sugar cane molasses was supplied. In other works, genetically recombinant bacteria were also employed to PHA, production using molasses. "
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    • "3.9 x 106 Da) and the lower degree of crystallinity (60% XC).Thus, the present data indicate that molasses and CSL could be alternatively used for PHB production by this bacterium with high PHB content and adequate properties of biopolymer from a low cost process. Gouda et al. (2001) used cane molasses and corn steep liquor, two of the cheapest substrates available in Egypt to reduce the cost of producing such biopolyesters. The effect of different carbon sources was studied and maximum production of PHB was obtained with cane molasses and glucose as sole carbon sources (40.8, 39.9 per mg cell dry matter, respectively). "
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    • "In the DAWM, the PHA production was observed in all the three selected strains. So it is established that the molasses alone can supply the required nutrients for growth as well as to some extent PHA production (Gouda et al., 2001). Comparatively better growth was observed in PHA detection media than DAWM and PHA production is considerably high in PHA detection media in all three selected bacterial strains provided that other conditions like molasses concentration (2%), ammonium sulphate (0.2%) concentration kept constant at pH 7.0 and at 37 °C. "
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