Centrate grown Chlorella fusca (Chlorophyta): Potential for biomass production and centrate bioremediation

• Published in: Algal research (Amsterdam) Vol. 39; p. 101458
• Main Authors: Peralta, Eduardo, Jerez, Celia G., Figueroa, Félix L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2019
• Subjects: Biomass productivity; Centrate bioremediation; Chlorella fusca; Lipids; Photosynthesis; Proteins; Proteins; Biomass productivity; Centrate bioremediation; Lipids; Photosynthesis; Chlorella fusca
• ISSN: 2211-9264; 2211-9264
• DOI: 10.1016/j.algal.2019.101458

This paper describes the ability of microalgae Chlorella fusca (Chlorophyta) to bioremediate centrate obtained by the centrifugation of sludge from an urban wastewater treatment plant. Microalgae were grown under solar radiation in UV transparent cylindrical vessels in a batch culture for 35 days at different centrate concentrations (33%–66%–100%) and compared to microalgae grown in a Basal bold medium (BBM) with ammonium (BBM-NH4) or nitrate (BBM-NO3) as the inorganic nitrogen source. Biomass productivity was evaluated as cell weight and cell numbers. Photosynthetic activity was measured by in vivo chlorophyll a fluorescence associated with photosystem II. The ionic composition of the media, total internal carbon, nitrogen, protein and lipid content were evaluated. Culture growth in centrate treatments presented a lag phase, but reached, under 100% centrate, a higher number of cells (296·106 cellsmL−1) and equal biomass production (3.5 gL−1) than control treatment cultures in the stationary phase. The photosynthetic status, expressed as maximal quantum yield (Fv/Fm), was maintained high throughout time in BBM-NO3 treatment whereas under 100% centrate it reached similar values in the stationary phase. Maximal electron transport rate (ETRmax), estimator of photosynthetic capacity, was higher in BBM-NO3 (with a maximum value of 10.2 mmol e−m−3 s−1), however 100%-C treatment reached similar values (8.6 mmol e−m−3 s−1). Lipid and Protein productivities were higher under BBM-NO3 (58.8 mg−1L−1d−1, 124.07 mg−1L−1d−1) and 100% centrate (42.5 mg−1L−1d−1, 119.92 mg−1L−1d−1). Nitrogen deficiency in 66 and 100% centrate grown algae was related to an increase of the lipid to protein ratio. Centrate as the culture media was demonstrated to be a good candidate for biomass growth i.e. after a period of adaptation, photosynthetic state and productivity were similar to those in a traditional culture media. The reduction of N and P in centrate shows a promising application for the depuration of centrate with a reduction of costs. •Centrate is a good culture media candidate for algal biomass production.•Photosynthetic yields after acclimation are similar than those in traditional media.•Lipid and protein productivities show the potential for commercial use of centrate.•Chlorella fusca is a good candidate for the biofiltration of centrate.