Cultivation of Chlorella protothecoides in anaerobically treated brewery wastewater for cost-effective biodiesel production

Abstract

The use of wastewater has been investigated to overcome the economic challenge involved with a production of microalgae-based biodiesel. In this study, to achieve economical biodiesel production along with effective wastewater treatment at the same time, anaerobically treated brewery wastewater (ABWW) was utilized as a low-cost nutrient source, in the cultivation of Chlorella protothecoides. About 96 and 90 % of total nitrogen and phosphorus in ABWW were removed, respectively, while C. protothecoides was accumulating 1.88 g L(-1) of biomass. The C. protothecoides grown in ABWW showed increases in cell size and cell aggregation, resulting in a near 80 % enhanced harvesting efficiency within 20 min, as compared with only 4 % in BG-11. In addition, the total fatty acid content of the C. protothecoides grown in ABWW increased by 1.84-fold (35.94 ± 1.54 % of its dry cell weight), relative to that of BG-11.

Scenedesmus obliquus microalga‐based biorefinery – from brewery effluent to bioactive compounds, biofuels and biofertilizers – aiming at a circular bioeconomy

“…The results are in accordance with previous reports on microalgae‐based BWW treatment, such as those by Raposo et al . and Darpito et al ., who both used Chlorella sp., and by Ferreira et al . and Marchão et al ., who used S. obliquus in batch and continuous cultivations.…”

“…For phosphorus, the removal undertaken by S. obliquus is significantly lower than the ones achieved by Raposo et al . and Darpito et al ., 54–66 and 90% respectively. However, the present results are in the range of phosphorus removal efficiencies presented by Ferreira et al .…”

Nutrient removal and microalgal biomass production from different anaerobic digestion effluents with Chlorella species

“…Harvesting cultivated biomass accounts for at least 20–30% of the total costs in producing microalgal biomass, and therefore, the biomass settleability is an important factor to consider, particularly in large-scale cultivation 7,37 . Chlorella species reportedly have good auto-settling properties, which, although not completely clarified, seems to be influenced by ecophysiological factors such as pH, ions, and co-existing bacterial species 38,39 .…”

“…The harvesting efficiency of the cultivated biomass by gravity settling was determined as described previously by Darpito et al . 7 . An 8-mL volume was taken from each culture and vigorously shaken in an 11-mL glass vial (diameter, 1 cm; height, 14 cm).…”

“…This indicates the potential of microalgae-based treatment as an economically as well as environmentally appealing method for BNR, without the need for an external carbon source. Several studies have investigated the application of microalgae to the treatment of AD effluents, and various microalgal species have shown effective removal of nitrogen and phosphorus (>83%) from different AD effluents 7–10 .…”