Production of biodegradable plastic from local strains of Bacillus megaterium

Issue Date

3-2004

Abstract

A study was conducted to test four local renewable materials as substrate for poly-β-hydroxybutyrate (PHB) production and to optimize and develop a bioprocess for production. Local agro-industrial by-products such as molasses, nata de coco spent liquor, whey and coconut water were tested separately and compared with the established medium. Results indicated coconut water was the best, producing the highest PHB yield in Bacillus megaterium strain GR149. In subsequent optimization studies in 2.5 L fermentor, it was shown that coconut water had to be supplemented with 2.0% glucose and 0.5% ammonium chloride and the pH had to be adjusted to 7.0. An optimum fermentation process was obtained at 32-h duration when conditions were set at 28 C, 200 rpm and 0.5 vvm. For extraction, acetone drying following alkaline hypochlorite digestion and prior to chloroform extraction showed the best polymer recovery. This developed bioprocess technology resulted in 37% reduction of the cost when compared with the established PHB production medium. Analysis confirmed the identity of the PHB products, giving molecular weights ranging from 302,000 to 727,000 g mole-1. PHB from GR149 exhibited differential scanning calorimetric profile of 167.95 C melting temperature and 72.53 C crystallization temperature and a tensile strength of 10.4 megaPascals.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Volume

87

Issue

1

Page

76-86

Document Type

Article

Language

English

Subject

Bacillus megaterium, Biodegradable plastic, Bioprocess, Coconut water, Fermentation, Poly-β-hydroxybutyrate (PHB) production, Ralstonia eutropha

Digital Copy

none

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