Complex evaluation of Nostoc linckia (Roth.) Born. et Flah. biomass, cultivated on waste water from recirculating aquaculture system

Abstract

The paper considers the possibility of cultivating Nostoc linckia (Roth.) Born. et Flah. on waste water from Recirculating Aquaculture System (RAS). Nostoc is a genus of cyanobacteria found in various environments that forms colonies composed of filaments of moniliform cells in a gelatinous sheath. The investigated algae was grown on the Fitzgerald’s artificial medium number 11 in the modification of Zehnder and Gorham and on the water from RAS, that was standardized with the indicators pH and total mineralization. It is noted that waste water contains a sufficient amount of biogenic elements for the cultivation of cyanobacteria. A complex scheme has been developed for the analysis of N. linckia biomass, taking into account the solubility of organic substances and the sequence of their extraction. The biomass dynamics, protein content, carbohydrates, lipids, chlorophyll a, carotenoids and phycobilin pigments in the culture of N. linckia are studied. The maximum content of total protein was noted on the 30th day of cultivation and was about 60% of the dry weight of algae. The content of chlorophyll a, and carotenoids in N. linckia cells was maximal at 16,2 mg/g and 9,5 mg/g dry weight, respectively. Also, the level of the main components of phycobilin pigments (phycoerythrin, phycocyanin and aloficocyanin) was determined. A comparative description of the productive indicators of periodic culture depending on its initial supply with basic elements of mineral nutrition has been carried out. When grown on waste water from RAS N. linckia culture, the content of basic nutrients does not significantly differ from the control values, but its biomass cost is much lower. Keywords: Nostoc linckia, waste water from RAS, complex evaluation