Temperate-zone cultivation of Oedogonium in municipal wastewater effluent to produce cellulose and oxygen

Abstract

Cultivation of the filamentous chlorophyte Oedogonium in municipal wastewater effluent is known to improve water quality and yield lipid- and protein-rich biomass for industrial applications. Chlorophyte celluloses, whose molecular organization and physical traits differ from those of plants, represent yet another valuable extractive, and algal oxygen production is of economic value in wastewater treatment. Consequently, we explored cellulose and oxygen production from Oedogonium biomass batch-cultivated in treated secondary municipal wastewater effluent. We compared biomass, cellulose, and oxygen production outside and within an adjacent greenhouse, under differing dissolved CO2 and pH conditions, and during temperate-zone seasonal change from summer through fall. Overall production did not differ within or outside the greenhouse, but outside production was higher in summer and lower in fall as air temperatures declined. Batch cultivation offered advantages, but high levels of mixing and CO2 were essential to maintain neutral pH for optimal algal growth and oxygen production.