Identification and characterization of pectin degradation enzymes from Paenibacillus amylolyticus strain 27C64 by whole-genome sequencing and genomic library screening

Pectin-rich agricultural waste could serve as a valuable biomass for the production of ethanol and other bioproducts if it can be efficiently degraded to its monomeric sugars. Paenibacillus amylolyticus strain 27C64, a potential source of pectinolytic enzymes, was previously isolated from the hindgut of Tipula abdominalis larvae (an aquatic detritivore). A genomic library was prepared from this organism, expressed in E. coli, and screened for pectinolytic activity. Two pectinase-positive clones were shown to produce pectate lyases (PelA and PelB) which were further characterized. PelB showed low amino acid sequence homology to other family I pectate lyases, but differed at a few key conserved sequences and displayed a unique ability to degrade both pectin and polygalacturonic acid. Recently, a high-throughput Illumina platform was used for whole-genome sequencing of this Paenibacillus strain in order to identify other potentially novel pectin degradation enzymes. The sequences of three pectinolytic enzymes not previously known to exist in this organism were identified through automated RAST annotation based on the SEED database. The annotated function of these enzymes is supported by high amino acid sequence homology to other putative pectinolytic enzymes. Synthesis, expression, and characterization of these enzymes is ongoing.