title: Use of cellulolytic marine bacteria for enzymatic pretreatment in microalgal biogas production.
abstract: In this study, we designed and evaluated a microalgal pretreatment method using cellulolytic bacteria that naturally degrades microalgae in their native habitat. Bacterial strains were isolated from each of two mollusk species in a medium containing 1% carboxymethyl cellulose agar. We selected nine bacterial strains that had endoglucanase activity: five strains from Mytilus chilensis, a Chilean mussel, and four strains from Mesodesma donacium, a clam found in the Southern Pacific. These strains were identified phylogenetically as belonging to the genera Aeromonas, Pseudomonas, Chryseobacterium, and Raoultella. The cellulase-producing capacities of these strains were characterized, and the degradation of cell walls in Botryococcus braunii and Nannochloropsis gaditana was tested with "whole-cell" cellulolytic experiments. Aeromonas bivalvium MA2, Raoultella ornithinolytica MA5, and Aeromonas salmonicida MC25 degraded B. braunii, and R. ornithinolytica MC3 and MA5 degraded N. gaditana. In addition, N. gaditana was pretreated with R. ornithinolytica strains MC3 and MA5 and was then subjected to an anaerobic digestion process, which increased the yield of methane by 140.32% and 158.68%, respectively, over that from nonpretreated microalgae. Therefore, a "whole-cell" cellulolytic pretreatment can increase the performance and efficiency of biogas production.
authors.affiliation: Laboratorio de Ecología Microbiana, Centro de Bioinnovación, Universidad de Antofagasta, Antofagasta, Chile.
authors.forename: Camilo
authors.initials: C
authors.lastname: Muñoz
authors.affiliation: Laboratorio de Ecología Microbiana, Centro de Bioinnovación, Universidad de Antofagasta, Antofagasta, Chile.
authors.forename: Catalina
authors.initials: C
authors.lastname: Hidalgo
authors.affiliation: Centro de Investigación Científico Tecnológico para la Minería (CICITEM), Antofagasta, Chile Laboratorio de Ecología Microbiana, Centro de Bioinnovación, Universidad de Antofagasta, Antofagasta, Chile.
authors.forename: Manuel
authors.initials: M
authors.lastname: Zapata
authors.affiliation: Chemical Engineering Department and Scientific and Technological Bioresource Nucleus, University of La Frontera, Temuco, Chile.
authors.forename: David
authors.initials: D
authors.lastname: Jeison
authors.affiliation: Laboratorio de Ecología Microbiana, Centro de Bioinnovación, Universidad de Antofagasta, Antofagasta, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Riquelme
authors.affiliation: Centro de Investigación Científico Tecnológico para la Minería (CICITEM), Antofagasta, Chile Laboratorio de Ecología Microbiana, Centro de Bioinnovación, Universidad de Antofagasta, Antofagasta, Chile mariella.rivas@cicitem.cl.
authors.forename: Mariella
authors.initials: M
authors.lastname: Rivas
mesh_terms: D000333:Aeromonas / Q000145:classification / Q000201:enzymology / Q000302:isolation & purification; D001673:Biodegradation, Environmental; D056804:Biofuels; D002480:Cellulase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D000460:Chlorophyta / Q000378:metabolism / Q000382:microbiology; D045247:Chryseobacterium / Q000145:classification / Q000201:enzymology / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000145:classification / Q000201:enzymology / Q000302:isolation & purification; D008697:Methane / Q000378:metabolism; D058086:Microalgae / Q000378:metabolism* / Q000382:microbiology*; D010802:Phylogeny; D011549:Pseudomonas / Q000145:classification / Q000201:enzymology / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D056804:Biofuels; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D002482:Cellulose; D002480:Cellulase; D008697:Methane