Xylanolytic psychrotrophs from andosolic sedge fens and moss heaths in Iceland

Abstract

AbstractNine xylanolytic bacterial strains were isolated from fen and heath soils in northern Iceland. They were found by 16S rRNA gene sequencing to belong to the generaPaenibacillus,Bacillus,Pseudomonas, andStenotrophomonas. Using a simple, plate-based semiquantitative assay with azo-crosslinked xylan as the substrate, it was determined that although isolated from cold environments, most of the strains displayed greater xylanolytic activity under mesophilic conditions, with only the paenibacilli displaying markedly cold-active xylanolytic activity. Indeed, for one isolate,Paenibacillus castaneaeOV2122, xylanolytic activity was only detected at 15°C and below under the conditions tested. Of the nine strains,Paenibacillus amylolyticusOV2121 displayed the greatest activity at 5°C. Glycohydrolase family-specific PCR indicated that the paenibacilli produced multiple xylanases of families 10 and 11, whereas a family 8 xylanase was detected inPseudomonas kilonensisAL1515, and a family 11 xylanase inStenotrophomonas rhizophilaAL1610.