Effects of organic matters in domestic wastewater on lipid/carbohydrate production and nutrient removal of Chlorella vulgaris cultivated under mixotrophic growth conditions

Abstract

BACKGROUND: The combination of wastewater treatment and algal biofuel production has received increasing attention in recent years owing to its many advantages. In order to clarify the influence of different organic pollutants such as carbohydrates, volatile fatty acids (VFAs) and proteins in domestic wastewater on the cultivation of Chlorella vulgaris, three simulated domestic sewages containing glucose, sodium acetate (NaAc) and protein respectively were prepared in this study to culture C. vulgaris in mixotrophic way. RESULTS:The biomass productivities of C. vulgaris cultured in wastewaters containing glucose and NaAc were 63.5 and 55.2 mg L −1 day −1 respectively, which were 2.61-and 2.27-fold larger than that achieved in photoautotrophic condition. Owing to the higher biomass productivity, better performance of nutrient removal was also achieved in wastewater containing glucose or NaAc. Different from glucose and NaAc, protein in the wastewater had no significant effect on C. vulgaris growth and nutrient removal. Chlorella vulgaris cultured in NaAc and glucose wastewaters achieved the highest lipid (17.35 mg L −1 day −1 ) and carbohydrate (18.75 mg L −1 day −1 ) productivities respectively, indicating that wastewater containing these two organic substances has certain advantages in microalgal liquid biofuel production. CONCLUSIONS: Organic matters in wastewater have important effects on microalgae growth and the chemical composition of algal cells. Carbohydrates and VFAs in wastewater can significantly promote the growth of C. vulgaris and promote the accumulation of lipid by microalgae. AnalysisThe microalgae concentration was determined using the optical density of the microalgae culture at 680 nm (OD 680 ). According to a previous study, the relationship between the dry biomass J Chem Technol Biotechnol 2019; 94: [3578][3579][3580][3581][3582][3583][3584]

A waste-to-wealth initiative exploiting the potential of Anabaena variabilis for designing an integrated biorefinery

“…The enhanced carbohydrate accumulation can also be partly accredited to the carbonaceous matters present in the wastewater, which was indicated by the TOC, BOD, and COD values. These observations are in agreement with the study of Peng et al 56 , where increased carbohydrate content of Chlorella vulgaris was reported under the mixotrophic growth condition using organic matters in the domestic wastewater. The elevated cellular carbohydrate content using AD medium, thus, compensated for the reduced biomass yield of the test cyanobacterium.…”

Combination of bicarbonate and low temperature stress induces the biosynthesis of both arachidonic and docosahexaenoic acids in alkaliphilic microalgae Dunaliella salina HTBS

“…Similar results were also obtained for protein content analysis (19.66% to 26.03%) (Figure 1D). With the addition of bicarbonate, the increased C/N ratio results in more lipid and carbohydrate biosynthesis for carbon storage with the excess energy (Peng et al, 2019;Singh et al, 2022;Xie et al, 2022). Although the lipid accumulation and protein biosynthesis present competitive relationships with each other, the increased profile of both lipid and protein content were observed in this study, possibly owing to the modified nitrogen content (750 mg/L), which was 10-fold higher than f/ 2 medium and promotes more intracellular conversion to protein (Vishwakarma et al, 2019).…”

Nutrient Removal by Algae-Based Wastewater Treatment

“…Organic carbon sources have a great influence on nutrient removal in mixotrophic cultivation. Peng et al [56] observed that nitrogen and phosphorus removal was better when supplemented with the mixotrophic culture of Chlorella vulgaris with glucose rather than protein or sodium acetate. Addition of glucose also enhanced the fixation of nitrogen and phosphorus in an artificial wastewater [57].…”