Abstract

A local white-rot fungus basidiomycete Pleurotus ostreatus MR3 was isolated from MacRitchie Reservoir Park, Singapore. Among all the ligninolytic activities, laccase was the only enzyme detected in the supernatant when the fungus was grown in liquid culture. This newly isolated white rot fungus was able to completely decolourise remazol brilliant blue R (RBBR) in-vivo on agar plates within five days and in the liquid culture (in the presence of inducers) within three days. The addition of inducers was able to enhance laccase production and therefore enhanced in-vivo RBBR decolourisation. Veratryl alcohol was shown to be the best inducer for laccase production with the maximum laccase activity reaching about 5.99 U/mL. Cu²⁺ also had a positive effect on laccase production, the laccase activity being enhanced to 5.24 U/mL. In-vitro RBBR decolourisation using the laccase from P. ostreatus MR3 was much comparable to that using the commercial laccase from Trameters versicolor.

Key words: Dyes, remazol brilliant blue R, Pleurotus ostreatus MR3, decolourisation, inducers, laccase activity.

Abbreviation

Abbreviations: RBBR, Remazol brilliant blue R; WRF, white rot fungi; PCR,polymerase chain reaction; SmF, submerged fermentation; ABTS, 2,2′-azino-di-[3-ethyl-benzothiazoline-(6)-sulfonic acid]; LiP, lignin peroxidase; MnP, manganese peroxidase.