title: Algae harvesting for biofuel production: influences of UV irradiation and polyethylenimine (PEI) coating on bacterial biocoagulation.
abstract: There is a pressing need to develop efficient and sustainable separation technologies to harvest algae for biofuel production. In this work, two bacterial species (Escherichia coli and Rhodococus sp.) were used as biocoagulants to harvest Chlorella zofingiensis and Scenedesmus dimorphus. The influences of UV irradiation and polyethylenimine (PEI)-coating on the algal harvesting efficiency were investigated. Results showed that the UV irradiation could slightly enhance bacteria-algae biocoagulation and algal harvesting efficiency. In contrast, the PEI-coated E. coli cells noticeably increased the harvesting efficiencies from 23% to 83% for S. dimorphus when compared to uncoated E. coli cells. Based on the soft-particle Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, an energy barrier existed between uncoated E. coli cells and algal cells, whereas the PEI coating on E. coli cells eliminated the energy barrier, thereby the biocoagulation was significantly improved. Overall, this work presented groundwork toward the potential use of bacterial biomass for algal harvesting from water.
authors.affiliation: John A. Reif, Jr. Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Agbakpe
authors.affiliation: John A. Reif, Jr. Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, United States.
authors.forename: Shijian
authors.initials: S
authors.lastname: Ge
authors.affiliation: John A. Reif, Jr. Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, United States. Electronic address: wzhang81@njit.edu.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Laboratory for Algae Research and Biotechnology, Department of Applied Sciences and Mathematics, Arizona State University, Mesa, AZ 85212, United States.
authors.forename: Xuezhi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: John A. Reif, Jr. Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, United States.
authors.forename: Patricia
authors.initials: P
authors.lastname: Kobylarz
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D002708:Chlorella / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D005427:Flocculation / Q000187:drug effects / Q000528:radiation effects; D011094:Polyethyleneimine / Q000494:pharmacology; D012240:Rhodococcus / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D044444:Scenedesmus / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D056804:Biofuels; D011094:Polyethyleneimine
keywords: Algal harvesting; Biocoagulation; Biofuel; Coagulation efficiency; DLVO