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Engineering broad-spectrum digestion of polyuronides from an exolytic polysaccharide lyase

MacDonald, Logan C., Weiler, Elizabeth B., Berger, Bryan W.
Biotechnology for biofuels 2016 v.9 no.1 pp. 43
Chlorophyta, Phaeophyceae, Stenotrophomonas maltophilia, alginate lyase, bioethanol, chemical degradation, digestion, energy efficiency, engineering, macroalgae, mutants, polyuronides, saccharification
BACKGROUND: Macroalgae represents a promising source of fermentable carbohydrates for use in the production of energy efficient biofuel. The primary carbohydrate in brown algae is the uronic acid-containing alginate, whereas green algae contains a significant amount of glucuronan. A necessary step in the conversion of these polyuronides to bioethanol is saccharification, which can be achieved by enzymatic or chemical degradation. RESULTS: Polysaccharide lyases are a class of enzymes which cleave uronic acid-containing glycans via a β-elimination mechanism, acting both endo- and exolytically on their substrates. In the present work, we characterize a putative alginate lyase from Stenotrophomonas maltophilia K279a (Smlt2602) and describe a H208F mutant that, in addition to cleaving alginate-based substrates, displays significant, exolytic glucuronan activity. CONCLUSIONS: To our knowledge this is the first polysaccharide lyase to act exolytically on glucuronan and is an attractive candidate for the broad-spectrum digestion of polyuronides into fermentable monomers.