Productivity of Microalgae Chlorella Sorokiniana When Growing on Chicken Manure Under Different Lighting Conditions

Abstract

The production of microalgae biomass on agricultural waste has a high potential, which is associated both with solving a number of environmental problems and also with obtaining a commercial effect. The purpose of the research is to determine the production characteristics of Chlorella sorokiniana microalgae when grown under different light conditions on a nutrient medium prepared on the basis of chicken manure. The research was carried out in the laboratories of the Federal Agricultural Kursk Research Center in 2020–2021. The object of the study is a culture of microalgae Chlorella sorokiniana (IPPAS C-1). Chicken manure in terms of dry weight contained 3.82 % of total nitrogen, 1.93 % – phosphorus, 55.26 % – organic matter. The toxic elements were within acceptable limits. A distinctive feature of the method of preparing a nutrient medium based on manure was its use without preliminary fermentation at a dose of 7 g/l. Photobioreactors with a volume of 5 liters of closed type with constant artificial lighting and 20 liters of open type with natural lighting were used for work. The culture layer for all variants of the experiment was 0.15 m. Artificial lighting was represented by HPS 150 W and energy-saving LED Aquael 10 W lamps. Illumination under artificial lighting was 20 and 40 klx, under natural lighting – 36 and 70 klx. When comparing different lighting sources, it was found that the use of a nutrient medium based on chicken manure made it possible to obtain a culture of Chlorella sorokiniana with a cell density from 38.67 to 62.66 million ml-1 under LED lighting, from 43.67 to 76.67 million ml-1 under HPS lighting and from 17.33 to 41.33 million ml-1 under natural lighting. Considering the three types of lighting, it should be noted that the most optimal way of Chlorella sorokiniana cultivation is on chicken manure under natural and LED lighting. Variants with a HPS lighting system were more energy-intensive even though they had a higher cell density.