Assessing the potential of Chlorella sp. for treatment and resource utilization of brewery wastewater coupled with bioproduct production

Abstract

Wastewater from various industries is the ideal substrate for the cultivation of microalgae, leading to efficient wastewater treatment and the production of a valuable microalgal biomass. However, further research is needed before wastewater can be used and treated on a large scale. The purpose of the paper was to explore the cultivation of the microalga Chlorella sp. in brewery wastewater (BWW) as well as under applied treatments of cultivating mode, dilution ratios, pretreatment method, and feeding strategies, and investigate the potential value of biomass obtained. Cultivation in BWW was initiated from 30% (v/v) loading while enrichment with 10% waste beer yeast supernatant (WYS) increased specific growth rate (μ) and biomass production, reaching 0.12 d−1 and 1.77 g L−1, respectively. Increasing BWW concentration up to 50% with 10% WYS can obtain the maximum biomass concentration of 2.03 g L−1 that is 0.14 g L−1 higher than 1.89 g L−1 of biomass in BG11. Even when the concentration of BWW reached 100%, biomass production can still reach 1.96 g L−1. In terms of BWW remediation, the maximum removal of ammonia nitrogen (NH4+-N), chemical oxygen demand, total nitrogen, and total phosphorus reached 94.38%, 88.52%, 96.71%, and 98.68%, respectively. Furthermore, the applied conditions determined the composition of Chlorella sp. biomass, which was mostly rich in lipid and carbohydrates. The maximum lipid, carbohydrate, and protein contents were 36.19%, 36.51%, and 19.77%, respectively, depending on culture conditions, and heterotrophic conditions were beneficial to protein accumulation in Chlorella sp. Photosynthetic fluorescence parameter electron transport rate was positively correlated with the biomass concentration of Chlorella sp.