Biotechnology and Bioprocess Engineering 2009, 14: 513-522 DOI/10.1007/s12257-008-0262-6 Extracellular Ligninolytic Enzymes by Lentinus polychrous Lév. under Solid-state Fermentation of Potential Agro-industrial Wastes and Their Effectiveness in Decolorization of Synthetic Dyes Rakrudee Sarnthima 1 *, Saranyu Khammuang 1 , and Jisnuson Svasti 2 1 Protein and Enzyme Technology Research Unit and Department of Chemistry, Mahasarakham University, Maha Sarakham 44150 Thailand 2 Center of Protein Structure and Function and Department of Biochemistry, Mahidol University, Bangkok 10400, Thailand ^Äëíê~Åí= Six agro-industrial wastes were evaluated as a support for ligninolytic enzyme production by the white-rot fungus iÉåíáåìë= éçäóÅÜêçìë Lév. under solid-state fermentation. Enzyme production was markedly different according to the substrate used. Rice bran (RB) yielded the highest laccase activity of 1,449 U/L (after 21 days of culture) with specific activity of 4.4 U/g substrate. Rice bran supplemented with rice husk (RH) (2:1 by wt) showed high laccase activity of 1,425 U/L with specific activity of 10.0 U/g substrate (after 17 days of culture). The crude enzyme of the RH-RB culture also contained manganese peroxidase (MnP) and manganese-independent peroxidase (MIP) activities in relative proportions of 1.9:1.4:1 of laccase:MnP:MIP, respectively. Zymogram studies showed the same isoenzyme pattern with these ligninolytic enzymes. The high enzyme production level and low substrate cost of SSF-iK= éçäóÅÜêçìë Lév. suggest that it has potential for industrial applications. Our studies showed that the crude enzyme from this culture exhibited áå=îáíêç decolorization of Indigo Carmine. The highest efficiency of dye decolorization was observed under alkaline conditions (pH 9.0) at an initial dye concentration of 10 mg/L. The rather high pH conditions and high efficiency in Indigo Carmine decolorization make the enzyme further interest for the applications in treatment of waste water from the textile industry, which contains synthetic dyes. © KSBB hÉóïçêÇëW=ä~ÅÅ~ëÉI=äáÖåáåçäóíáÅ=ÉåòóãÉI Lentinus polychrous i¨î.I=ëçäáÇJëí~íÉ=ÑÉêãÉåí~íáçåI=~ÖêáÅìäíìê~ä=ï~ëíÉëI= = ÇÉÅçäçêáò~íáçå= INTRODUCTION Among the ligninolytic enzymes, laccase (EC 1.10.3.2; benzenediol:oxygen oxidoreductases), a copper-containing oxidase, is of great interest due to its broad range of substrates, which include polyphenols, aromatic amines, polycyclic aro- matic hydrocarbons, and synthetic dyes [1]. Moreover, other non-phenolic compounds and redox mediators such as N- G`çêêÉëéçåÇáåÖ=~ìíÜçê= Tel: +66-43-754246 Fax: +66-43-754246 e-mail: rakrudee.s@msu.ac.th hydroxybenzothiazone and 2,2-azinobis (3-ethylbenzothiazo -line-6-sulfonate) diammonium salt (ABTS) have also been reported to be substrates [2]. This enzyme shows high potential for application in various industries, such as pulp and paper delignification [3,4], dye decolorization, waste water, and contaminated soil treatment [5-7], as well as uses in organic synthesis [8], biosensor applications [9], and inhibition of HIV-1 reverse transcriptase [10]. However, a major limitation for extensive industrial application of fungal enzymes is their high cost. Therefore, culture conditions need to be optimized to increase the productivity of enzymes and to reduce the investment cost.