Abstract

CARDONA ECHAVARRIA, Ana Carolina; MORA MARTINEZ, Amanda Lucía  and  MARIN MONTOYA, Mauricio. Molecular Identification of Polyhydroxyalkanoate-Producing Bacteria Isolated from Dairy and Sugarcane Residues. Rev. Fac. Nac. Agron. Medellín [online]. 2013, vol.66, n.2, pp.7129-7140. ISSN 0304-2847.

Polyhydroxyalkanoates (PHAs) are thermostable bioplastics produced by bacteria and stored as inclusion bodies to serve as a reserve carbon source. These compounds are a good alternative to non-biodegradable synthetic plastics. In this work, the presence of PHAs-producing bacteria in whey, sugar-cane molasses, cachaza and bagasse was investigated. Bacteria were isolated using a minimal medium supplemented with 2% glucose and 1 mL mL-1 Nile red (0.1%). Colonies exhibiting fluorescence at 340 nm were further analyzed by fluorescence microscopy with Nile blue. When positive for both tests, bacterial isolates were classified as PHAs producers and their 16S rDNA sequenced. For selected isolates, the presence of the phaC gene was confirmed by PCR. A total of 38 strains, grouped into 18 different morphotypes, were identified as PHA producers. Bacteria belonging to Lactococcus, Klebsiella, Pseudomonas, Enterobacter and Enterococcus genera were isolated from whey and Bacillus, Enterobacter, Pantoea, Klebsiella and Gluconobacter from sugar cane residues. The phaC gene was detected by PCR in 16 bacteria with type I and IV arrangements. This work opens up the possibility of using the isolated bacteria as an environmentally sustainable alternative for the disposal of agro-industrial residues as well as an additional income source.

Keywords : 16S rDNA; bagasse; molasses; PCR; phaC; whey.

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