The effect of adding bacteria (nitrogen-fixing bacteria, amylolytic, and phosphate solubilizing bacteria) and different culture media on the growth of the microalgae Chlorella vulgaris

Department of Biology, State University of Malang, Malang, 65145, Indonesia

^* Corresponding author : sitoresmi.prabaningtyas.fmipa@um.ac.id

Abstract

Microalgae have the potential to be developed. As a source of biofuels, medicines, cosmetics, sources of food and feed, it is necessary to optimize microalgae growth to increase microalgae growth. Bacteria can increase microalgae growth through various mechanisms such as producing CO₂, degrading organic molecules, providing vitamin B12, and preventing oxidative stress. One important factor for the growth of microalgae is culture media. Therefore, it is necessary to do research to find the medium culture that gives the highest density of microalgae cells. The research objective was to determine the effect of the addition of bacteria and culture media on the growth of Chlorella vulgaris. Our research used microalgae-bacterial coculture in Guillard and Gusrina medium. The culture conditions is set 12 hours without an aerator, 12 hours with an aerator; 16 hours of light; 8 dark hours; light intensity 2700 lux. The results of the study showed the coculture treatment had higher cell density of about 3.8 × 10⁷ cells/mL and Gusrina medium showed the highest cell density at about 4.6 × 10⁷ cells/mL. The addition of bacteria was able to increase the growth of microalgae and Gusrina medium showed a good growth medium for C. vulgaris.