The effect of psychrotolerant methylotrophic bacteria on the growth, pigment content and accumulation of protein and carbohydrates in the microalgae chlorella vulgaris

The study is devoted to the effect of six psychrotolerant methylotrophic bacteria isolated from samples of moss-lichen community and water bodies, collected at the territory of Antarctic oases and mountainous region of the Altai republic on the growth, pigment content and accumulation of protein and carbohydrates by the green microalgae Chlorella vulgaris at temperatures of +10°C and +20°C. Standard growth curves of chlorella without bacterial suspension at +20°C and +10°C reached the stationary growth phase on days 5-6 and 9, respectively, reaching 30 and 16*106 cells/ml. It was found that five of the six psychrotolerant strains had no effect on the number of chlorella cells, pigment content and protein concentration when co-cultured with microalgae at the temperature of +10°C. A positive effect was found only for xPrg3, in particularly on the carbohydrate concentration. A negative effect of Bel19 on the cell number and pigment content at +10°C was also found. Inoculation of chlorella under the temperature of +20°C with same bacterial strains lead to increase in: cell number with the strain xPrg3, chlorophyll a with Bel19 (119% of the control), carbohydrates with the isolate xPrg17 and intracellular protein content with Al5, Bel19, Bel62 and xPrg17.