title: Maximizing the utilization of Laminaria japonica as biomass via improvement of alginate lyase activity in a two-phase fermentation system.
abstract: Brown seaweed contains up to 67% of carbohydrates by dry weight and presents high potential as a polysaccharide feedstock for biofuel production. To effectively use brown seaweed as a biomass, degradation of alginate is the major challenge due to its complicated structure and low solubility in water. This study focuses on the isolation of alginate degrading bacteria, determining of the optimum fermentation conditions, as well as comparing the conventional single fermentation system with the two-phase fermentation system which is separately using alginate and mannitol extracted from Laminaria japonica. Maximum yield of organic acids production and volatile solids reduction obtained were 0.516 g/g and 79.7%, respectively, using the two-phase fermentation system in which alginate fermentation was carried out at pH 7 and mannitol fermentation at pH 8. The two-phase fermentation system increased the yield of organic acids production by 1.14 times and led to a 1.45-times reduction of VS when compared to the conventional single fermentation system at pH 8. The results show that the two-phase fermentation system improved the utilization of alginate by separating alginate from mannitol leading to enhanced alginate lyase activity.
authors.affiliation: Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Republic of Korea.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Oh
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Republic of Korea.
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Republic of Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang, Republic of Korea. jmpark@postech.ac.kr.
authors.forename: Jong Moon
authors.initials: JM
authors.lastname: Park
mesh_terms: D000464:Alginates / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D005232:Fatty Acids, Volatile; D005285:Fermentation; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D007795:Laminaria / Q000737:chemistry* / Q000382:microbiology*; D008353:Mannitol / Q000378:metabolism*; D011133:Polysaccharide-Lyases / Q000378:metabolism*
chemical_list: D000464:Alginates; D001426:Bacterial Proteins; D005232:Fatty Acids, Volatile; D006603:Hexuronic Acids; D008353:Mannitol; D020723:Glucuronic Acid; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase
keywords: Alginate; Alginate lyase; Brown macro-algae; Two-phase fermentation system; Volatile fatty acids