Endo-xylanase enzyme from marine actinomycetes and its potential for xylooligosaccharide production

Abstract

Marine microorganism was emerging as the great source for the discovery of novel enzyme. The search and discovery of new enzymes derived from actinomycetes have received much attention nowadays due to a growing need for applications in various industries including food industry. Endo-β-1,4-xylanases is considered one of critical enzyme involves in the degradation of xylan that is able to cleave the β-1,4-glycosidic linkages in the xylan backbone resulting in various xylooligosaccharides and xylose. Screening and characterization of novel actinomycetes that is capable of producing high xylanase are necessary to produce xylooligosaccharides from hemicellulose hydrolysis process. The objective of this research is screening and characterizing of novel marine actinomycetes from working culture of Research Center for Biotechnology, Biotechnology Culture Collection (BTCC) that are capable of producing high-level hemicellulase-degrading enzymes, especially endo-xylanase enzyme. Approximately, 70 strains from Indonesia marine Actinomycetes have been screened by using congo red, SDS-PAGE and zymogram methods. Of these 70 strains, 3 strains were successfully identified that is capable in producing high level of xylanase enzymes based on the diameter of clear zone more than 1.5 cm on xylan plate medium pH 5.0 and 6.0. Three strains from marine Actinomycetes were identified based on analysis a 16S rRNA gene sequence revealed that all of strains belonging to the genus Streptomyces. Strain 47 is closely related with Streptomyces variabilis (98%). All strains had ability to produce xylanase at optimum pH 5.0 and temperature range between 50-60 °C with range activity from 2.5 – 4.3 U/mL. Each isolate had a molecular weight from 20-50 kDa based on SDS-PAGE and zymogram analysis. Based on TLC analysis using beechwood xylan, each isolate had ability to produce xylooligosaccharides. These characterizations showed that these isolates are potentially used for xylooligosaccharides productions. Strain 47 was selected for the next analysis for molecular cloning based on the pattern and results of TLC clearer then strain 41 and strain 42.