Efeitos de parâmetros físicos e químicos na produção de pigmentos e biomassa de três bactérias isoladas de solos amazônicos

Abstract

The acceptance of many products in the market is directly related to their appearance, and among the most important features we can mention the color. Due to the current global trend of wanting to replace the artificial for the natural, the food industry, textile, pharmaceutical and cosmetic are seeking natural products that do not cause harm to health and that are friendly to the environment. An alternative source for obtaining natural pigments are bacteria, due to the advantages they have in terms of their high growth rate, geographic independence, controllable conditions, genetic manipulation, and reduced cost through the use of less expensive growth media. The present study aimed to test different physical and chemical parameters, identifying those that influence positively on cell growth and pigment production of three bacteria isolated from Amazonian soils (Serratia marcescens, Microbacterium sp. and Burkholderia sp). The tests were performed using nutrient broth as growing medium, selected as the base medium, testing different sources of carbon, nitrogen, temperature and pH. Samples were taken at 24, 48 and 72 hours after incubation, by measuring the cell growth by means of OD (optical density) at 600 nm, and pigment production by extraction with polar solvents when necessary, and reading the OD in the wavelength for each case (red at 470 nm for S. marcescens, yellow at 440 nm for Microbacterium sp., and purple at 470 nm for Burkholderia sp). In Serratia marcescens the highest biomass was obtained with sucrose and glucose as carbon source, yeast extract as a nitrogen source at a temperature of 25°C and a pH of 7 and 8. The growth parameters that influenced positively in the production of pigment was the use of soluble starch as carbon source, yeast extract as a nitrogen source at a temperature of 25°C and pH 8. Regarding to Microbacterium sp., the best cell growth occurred in the presence of sucrose as carbon source, yeast extract as nitrogen source, at a temperature of 25 and 30°C with a pH between 6 and 8. Soluble starch as carbon source, yeast extract as a nitrogen source in a temperature range between 20-30 °C and a pH between 6 and 9, favored the pigment production. As to Burkholderia sp., cell growth was favored by the use of glucose as carbon source, yeast extract as a nitrogen source at a temperature of 20-25°C, and a pH of 6. The higher pigment yields were observed when lactose was used as carbon source, yeast extract as a nitrogen source at a temperature of 20 and 25°C, and a pH between 6 and 7. These results can be used in order to improve the yields in the production of pigments of interest by the bacterial species studied.

Key words: microbial metabolism, biopigment, Amazon microbiota, biotechnology products.