Microbacterium oxydans, a novel alginate- and laminarin-degrading bacterium for the reutilization of brown-seaweed waste.
There is a growing demand for the efficient treatment of seaweed waste. We identified six bacterial strains from the marine environment for the reutilization of brown-seaweed waste, and the most potentially useful strain, Microbacterium oxydans, was chosen and further investigated. Plate assays indicated that this bacterial isolate possessed both alginate lyase and laminarinase activities. The optimal inoculum size, pH, temperature and substrate concentration for the degradation of brown-seaweed polysaccharides by the isolate were as follows: 20% (v v(-1)), pH 6.0, 37 °C, and 5 g L(-1) for alginate and 20% (v v(-1)), pH 6.0, 30 °C, and 10 g L(-1) for laminarin, respectively. During 6 d in culture under the optimal conditions, the isolate produced 0.17 g L(-1) of reducing sugars from alginate with 11.0 U mL(-1) of maximal alginate lyase activity, and 5.11 and 2.88 g L(-1) of reducing sugars and glucose from laminarin, respectively. In particular, a fair amount of laminarin was degraded to glucose (28.8%) due to the isolate's exolytic laminarinase activity. As a result, the reutilization of brown-seaweed waste by this isolate appears to be possible for the production of reducing sugars as a valuable resource. This is the first study to directly demonstrate the ability of M. oxydans to degrade both alginate and laminarin.
Department of Biotechnology, Pukyong National University, Busan 608-737, Republic of Korea.
Eun Jung
EJ
Kim
Ahmad
A
Fathoni
Gwi-Taek
GT
Jeong
Hyun Do
HD
Jeong
Taek-Jeong
TJ
Nam
In-Soo
IS
Kong
Joong Kyun
JK
Kim
D000192:Actinomycetales / Q000201:enzymology / Q000378:metabolism*; D000464:Alginates / Q000378:metabolism*; D001673:Biodegradation, Environmental; D044602:Cellulases / Q000378:metabolism; D003247:Conservation of Natural Resources; D005936:Glucans; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D011133:Polysaccharide-Lyases / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D012624:Seaweed / Q000378:metabolism*; D013696:Temperature; D018505:Waste Management / Q000379:methods*
D000464:Alginates; D005936:Glucans; D006603:Hexuronic Acids; D011134:Polysaccharides; D020723:Glucuronic Acid; C008247:laminaran; D044602:Cellulases; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase
Biodegradation; Brown-seaweed waste; Exolytic laminarinase; Microbacterium oxydans; Reutilization