title: Harvesting freshwater Chlorella vulgaris with flocculant derived from spent brewer's yeast.
abstract: One of the key bottlenecks of the economically viable production of low added value microalgal products (food supplements, feed, biofuels) is the harvesting of cells from diluted culture medium. The main goals of this work were to prepare a novel flocculation agent based on spent brewer's yeast, a brewery by-product, and to test its harvesting efficiency on freshwater Chlorella vulgaris in different environments. The yeast was first autolyzed/hydrolyzed and subsequently chemically modified with 2-chloro-N,N-diethylethylamine hydrochloride (DEAE). Second, optimal dosage of modified spent yeast (MSY) flocculant for harvesting C. vulgaris was determined in culture media of various compositions. It was found that the absence of phosphorus ions decreased (0.4 mg MSY/g biomass), while the presence of algogenic organic matter (AOM) increased (51 mg MSY/g biomass) the required dosage of flocculant as compared to complete mineral medium with phosphorus and without AOM (12 mg MSY/g biomass).
authors.affiliation: Department of Biotechnology, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague, Czech Republic.
authors.forename: Gita
authors.initials: G
authors.lastname: Prochazkova
authors.affiliation: EcoFuel Laboratories Ltd., Ocelarska 392/9, 190 00 Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Kastanek
authors.affiliation: Department of Biotechnology, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague, Czech Republic. Electronic address: tomas.branyik@vscht.cz.
authors.forename: Tomas
authors.initials: T
authors.lastname: Branyik
mesh_terms: D018533:Biomass; D048408:Chlorella vulgaris / Q000254:growth & development*; D003470:Culture Media / Q000737:chemistry; D005427:Flocculation; D005618:Fresh Water; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D055672:Static Electricity
chemical_list: D003470:Culture Media; D009930:Organic Chemicals
keywords: Chlorella; Flocculation; Microalgae harvesting; Spent brewer’s yeast; Surface modification