Evaluation of biopolymer-producing bacteria deposited in the Microbiological Culture Collection

Bacteria are important organisms in various industrial processes due to their ability to produce a wide range of enzymes. In this context, the present work evaluates 100 bacteria deposited in the Microbiological Culture Collection of Amazonas State University - UEA, regarding the production of biopolymers such as Polyhydroxyalkanoate - PHA. For the production of biopolymers, a mineral medium was used and staining was done with Sudan black B and Nile Red for observation by optical and confocal microscopy. The production of biopolymers was carried out in 50 mL aliquots using mineral medium, with sucrose, glucose and glycerol as carbon source, cultivated for 72 hours at 36 °C with stirring at 140 rpm. The biopolymer extraction was performed with formaldehyde and sodium hypochlorite and precipitated with methanol. The best results were achieved with isolates UEA-101, of 47.78%, and UEA-10, of 35.09% of extracted polymer. UEA-65 produced the greatest volume, with 1.87 g of cell mass, 0.44 g of biopolymer and yield of 23.5%, using sucrose as carbon source. Chromatographic analyses showed the existence of levuric acid and methyl 3- hydroxyhexadecanoatein several of the studied bacteria. Identification of biopolymer-producing bacteria by sequencing the 16S rRNA gene showed that they belong to the genera Paenibacillus, Enterobacter, Serratia and Bacillus. The isolates UEA-10 and UEA-65, belonging to the Bacillus genus, and UEA-101, belonging to the Serratia genus, had the best biopolymer production.