Screening of lipid - rich algae for lipid production in seafood wastewater

Abstract

The ecological distribution, diversity and capacities of lipid production and nutrients removal of algae associated with freshwater habitats in southern Vietnam were investigated. Twenty four algal strains belonging to 7 genera were isolated from waster samples obtained from 8 sites. It was found that species composition and abundance were specific for each site. Zoo pond (Ho Chi Minh city) and Da Lake (Binh Duong province) showed the highest diversity and abundance. This result suggested that microhabitat (pond, lake, damp, etc.) showed greater influences on algal community than the environment of the location where the sample was taken (e.g. province/city). The 24 collected algal strains were cultured in Chu 13 medium and their growth performances were determined via optical density (OD) and dry cell weight methods. The obtained results revealed that all the studied algae had fast growth rates since their doubling times ranged from 9-12 days compared with 14-21 days in other researches. In term of lipid production (determined by Bligh and Dyer method), all the 24 algal strains had capacity to produce lipid with the contents ranging from 13.9% to 31.0%; of which three strains produced considerable high lipid contents were Scenedesmus sp. (31.0%), Chlorococcum sp. (30.6%) and Chlorella sp. (20.8%). Based on growth rate performance, biomass production and lipid content, Chlorococcum sp was selected for further studies. Nutrients (N and P) removal capacity of this species in seafood wastewater (both treated and untreated forms) was investigated. The results showed that this algal species could remove 60.7% of total nitrogen and 54.0% of total phosphorus in seafood untreated wastewater culture; and 88.2% of total nitrogen and 93.8% of total phosphorus in seafood treated wastewater culture; and performed lipid contents of 35.5 and 32.7% in treated wastewater and untreated wastewater cultures, respectively.