Molecular Identification of Polyhydroxyalkanoate-Producing Bacteria Isolated from Dairy and Sugarcane Residues ; Identificación Molecular de Bacterias Productoras de Polihidroxialcanoatos en Subproductos de Lácteos y Caña de Azúcar

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. ; Los polihidroxialcanoatos (PHAs) son bioplásticos termoestables sintetizados por algunas bacterias, que los acumulan como reservas de carbono en forma de inclusiones citoplasmáticas. Estos compuestos se constituyen en una opción para la sustitución de polímeros sintéticos no biodegradables. En este trabajo se evaluó la presencia de bacterias productoras de PHAs en lactosueros derivados de la producción de quesos, y en melaza, cachaza y bagazo de caña de azúcar. El aislamiento bacteriano se realizó en medio mínimo de sales suplementado con glucosa al 2% y 1 mL mL-1 de rojo Nilo (0,1%). Las colonias que presentaron fluorescencia a 340 nm en este medio, se evaluaron nuevamente mediante microscopía de ...