Genome sequence analysis for bioprospecting of marine bacterial polysaccharide-degrading enzymes (Chapter 2)

Abstract

Complex polysaccharides, such as agar, alginate, carrageenan, chitin, xylan, etc., are abundantly present in marine algae and crustaceans. Degradation of these polysaccharides is attributed to microbial agarase, alginate lyase, carrageenase, chitinase, and xylanase, respectively. Conventional dye-based plate assay for the screening/detection of microbes secreting these polysaccharide-degrading enzymes has many limitations as only individually produced extracellular enzymes could be identified. However, genome sequencing and annotation would provide holistic identification of polysaccharide-degrading genes in organisms. As the genome annotation would give the sequence of the genes, the identified genes encoding polysaccharide-degrading enzymes would be characterized on genomic level. Using the genome sequencing strategy, polysaccharide-degrading genes are identified and characterized from many marine bacteria, including Saccharophagus degradans 2-40 sup(T), Microbulbifer mangrovi DD-13 sup(T), Microbulbifer elongatus HZ11, etc. These bacterial genomes harbor an array of genes specific for multiple polysaccharide degradation. Furthermore, genome sequencing and functional annotation enable a comprehensive classification of polysaccharide-degrading genes into appropriate carbohydrate-active enzymes (CAZymes), families facilitating a holistic understanding of their ecological role, and exploiting them for creating novel technologies.