Mangrove Actinomycetes as the Source of Ligninolytic Enzymes

Abstract

Twenty actinomycete cultures were isolated from marine and mangrove areas and they were screened for the production of lignin degrading enzymes. The plate assay, using guaiacol as substrate, had been identified as an effective method for the screening of ligninolytic actinomycetes. Six isolates were found to be producing Lignin peroxidase of which four cultures were showing laccase activity too. Out of the twenty isolates screened, only one isolate produced manganese peroxidase. A newly isolated mangrove actinomycete Streptomyces psammoticus (coded NJP 49) capable of producing all the three major ligninolytic enzymes like Lignin peroxidase (LiP), Laccase and Manganese peroxidase (MnP) had been selected. Although S. psammoticus was found to be a potent producer of LiP and laccase, owing to the limited works carried out on MnP from actinomycetes, we had selected MnP for further studies and the crude characteristics of the MnP of this isolate were studied. The enzyme exhibited maximum activity at pH 7.0 and at temperature of 30 °C. The stability studies indicated that the enzyme was stable in the pH range of 7.0-7.5 and temperature range of 25 °C-40 °C.