title: Harvesting of microalgae by flocculation with poly (γ-glutamic acid).
abstract: In an effort to search for an efficient and environmentally friendly harvesting method, a commercially available microbial flocculant poly (γ-glutamic acid) (γ-PGA) was used to harvest oleaginous microalgae. Conditions for flocculation of marine Chlorella vulgaris and freshwater Chlorella protothecoides were optimized by response surface methodology (RSM) and determined to be 22.03 mg L(-1) γ-PGA, 0.57 g L(-1) biomass, and 11.56 g L(-1) salinity, and 19.82 mg L(-1) γ-PGA and 0.60 g L(-1) biomass, respectively. Application of the two optimized flocculation methods to Nannochloropsis oculata LICME 002, Phaeodactylum tricornutum, C. vulgaris LICME 001, and Botryococcus braunii LICME 003 gave no less than 90% flocculation efficiency and a concentration factor greater than 20. Micrographs of the harvested microalgal cells showed no damage to cell integrity, and hence no lipid loss during the process. The results show that flocculation with γ-PGA is feasible for harvesting microalgae for biodiesel production.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, No. 5, Xinmofan Road, Nanjing 210009, People's Republic of China.
authors.forename: Hongli
authors.initials: H
authors.lastname: Zheng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Gao
authors.forename: Jilong
authors.initials: J
authors.lastname: Yin
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Tang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Ji
authors.forename: He
authors.initials: H
authors.lastname: Huang
mesh_terms: D000704:Analysis of Variance; D059001:Aquatic Organisms / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D018533:Biomass; D018929:Cell Culture Techniques / Q000379:methods*; D002708:Chlorella / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D005427:Flocculation / Q000187:drug effects; D005618:Fresh Water; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D058086:Microalgae / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D054712:Salinity; D013045:Species Specificity; D013997:Time Factors
chemical_list: C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid