| Congresso Brasileiro de Microbiologia 2023 | Resumo: 922-1 | ||||
Resumo:Carotenoids are lipophilic pigments that can be produced by various microorganisms and plants. Due to their characteristics, these compounds can exhibit biological activities such as antioxidant, anti-inflammatory, and antitumor properties, making their production and application of great interest to the food, pharmaceutical, and cosmetic industries. This study aimed to evaluate the stress caused by different light sources on astaxanthin production by the yeast Phaffia rhodozyma in submerged culture. The yeast culture was activated in 500 mL Erlenmeyer flasks containing 100 mL of YPD (Yeast Peptone Dextrose) liquid medium, agitated at 300 rpm at 22ºC for 48 hours using an orbital shaker (Amerex-Gyromax 737R, Lafayette, CA, USA). The culture medium used for astaxanthin production was composed of the following per liter of distilled water: glucose (20 g), xylose (20 g), peptone (5 g), yeast extract (5 g), and malt extract (3 g). The microorganism was inoculated at a cellular concentration of 10% (v/v) in 50 mL of medium in 125 mL Erlenmeyer flasks and incubated on an orbital shaker for 120 hours. Samples were taken every 24 hours for each of the five study conditions. The influence of five LED light colors (Reflector 100w RGB, TOP LIGHT) was evaluated, namely, white, green, red, blue, and the absence of light. After the cultivation, the medium was centrifuged (7000 rpm, 5 min at 25ºC) using a Hitachi CR-22 N centrifuge (Tokyo, Japan). The supernatant was used for pH determination and sugar concentration analysis (glucose and xylose), while the biomass was stored in 50 mL Falcon tubes in a freezer at -80ºC to completely inactivate the yeast and subsequently extract and quantify the carotenoid and metabolites. Carotenoids were extracted using solid-liquid extraction with acetone as the solvent. The presence of light increased carotenoid production by P. rhodozyma, likely due to the protective mechanism generated by cellular stress caused by reactive species produced by light exposure. Red LED light was determined to be the most effective for astaxanthin production and resulted in the highest carotenoid production, even with the lowest biomass obtained. This indicates that the microorganism diverted the use of nutrients from the medium to cellular defense through carotenoid production, at the expense of its growth. In conclusion, light plays a crucial role in inducing stress on the microorganism, leading to carotenoid production, especially astaxanthin Palavras-chave: carotenoids, bioprocess, light stress Agência de fomento:FAPESP (2021/06686-8) | |||||