Immobilization of Chlorella sorokiniana AK-1 in bacterial cellulose by co-culture and its application in wastewater treatment

Abstract

BackgroundTaiwan's livestock industry has played an important role in agricultural development in the past decades. In addition to bringing prosperity and huge benefits to the countryside, it also generates wastewaters that cause eutrophication in water bodies. Bioremediation of wastewaters by immobilized microalgae has proven to be beneficial for high-strength wastewaters. MethodsIn situ immobilization of Chlorella sorokiniana AK-1 in bacterial cellulose (BC) was performed by co-culture with BC producing Gluconacetobacter xylinus using molasses as a carbon source. BC immobilized AK-1 was further applied for the treatment of dairy manure wastewater. Significant findingsMolasses at 5 g/L were utilized for high yield BC production by G. xylinus. The alkaline nature of the cultivation medium in the presence of molasses resulted in highly porous cellulose that facilitated microalgal attachment and growth. Bacterial HS medium and the microalgal BG-11 medium, mixed in a ratio of 1:1 resulted in effective granule formation with optimal microalgal density. The B50 granules obtained were applied for 50% dairy manure wastewater. The removal efficiency for total carbon, nitrogen and phosphorus with B50 microalgal granules were 50.93, 82.56 and 81.48%, respectively. Thus, microalgae immobilized on bacterial cellulose are effective for the bioremediation of high-strength wastewaters.