Phycoremediation of alcohol distillery wastewater with a novel Chlorella sorokiniana strain cultivated in a photobioreactor monitored on-line via chlorophyll fluorescence

Abstract Possibilities of alcohol distillery wastewater (ADW) bioremediation with a new Chlorella sorokiniana from White Sea cultivated in semi-batch mode in a high-density photobioreactor monitored on-line via chlorophyll fluorescence were investigated. Upon inoculation of the ADW, a stable alga-bacterial consortium was formed. A decrease in chemical oxygen demand (COD) of the ADW from 20 000 to ca. 1500 mg L − 1 was achieved over four days with a decline in nitrate (> 95%), phosphate (77%) and sulfate (35%). Minimal pre-treatment of the ADW (adjustment to 6.0–7.0 pH) was necessary. Kinetics of COD decline and growth of microalga on ADW as well as chlorophyll and fatty acid (FA) composition of the biomass were studied. Cultivation on ADW increased the unsaturation of the FA of the microalga cell lipids rendering the biomass of C. sorokiniana cultivated on ADW a suitable feedstock for biodiesel production. Measurement of variable chlorophyll fluorescence was shown to be a sensitive method for monitoring of the physiological condition of the microalgae grown on ADW. The cultivation conditions facilitating ADW bioremediation with the microalga were investigated. The advantages and limitations of the proposed process for ADW treatment are discussed in view of the findings obtained.