Laccase Production By White Rot Fungi Cerrena Sp.BBP6 And Its Application

Laccase belongs to a group of enzymes called blue copper oxidases which is capable of oxidizing phenolic and non-phenolic substrates.Due to its ability to catalyze the oxidation of a wide variety of substrates,laccase is used for various industrial applications including detoxification of industrial effluents,bleaching of paper pulp,and decolorization of synthetic dyes.In this study,the aim is to increase laccase production by optimizing culture conditions and apply laccase in dye decolorization and lignin degradation.Laccase activity of 20333U/L could be achieved in synthetic medium which has been optimized.In order to enhance laccase production,the medium was further modified to monitor the effect of inducers on laccase production.All the inducers including ethanol,Cu²⁺,aromatic inducers stimulated laccase production.However,Cu²⁺was the best inducer which increased laccase activity by 1.72 folds as compared to the control which lacked inducers.In order to furthe enhance laccase production,efficiency of laccase production was tested among synthetic medium,PDB medium and tomato medium with Cu²⁺.The highest laccase activity and protein concentration were obtained in tomato medium,127.6U/mL and 387.9ug/mL respectively.Laccase was used in decolorizing the different dyes.The effect of pH on laccase decolorization was experimented.Results have shown that different dyes have different optimum pH,but most of them were in the acidic range.Crude laccase showed good activity in synthetic dye color removal,decolorizing Xylene Cyanol?81.1%?,Bromophenol Blue?41.37%?and RBBR?68.46%?without the addition of mediators in 30 min.Decolorization rates of dyes in this paper were significantly improved by adding HBT,being more than 70%.The decolorization rates of Fast Green and Azure B with the addition of 0.1%HBT were 92.84%and 81.49%respectively.To our current knowledge,treatment of OPEFB with laccase has not yet been reported.The use of OPEFB as a substrate in addition of laccase treatment for production of cellulase and hydrolysate was studied in this paper which aims to decrease the cost of cellulase production and improve sugar yield.Using the OPEFB as substrate to produce cellulase,the cellulase activity was improved from12.56U/mL to 15.7U/mL with the addition of 0.5U/mL laccase.Laccase was also employed in combination with cellulase to act on OPEFB to produce hydrolysate.Successive?laccase and cellulase individually?and simultaneous?laccase together with cellulase?methods were investigated and the results showed that successive treatment improved cellulose conversion and the glucose concentration increased from 12.2g/L to 15.93g/L with 5U/mL laccase and cellulase successive treatment.The effects of different hydrolysis between Laccase-OPEFB and industrial hydrolysis on Yeast growth,sugar consumption and ethanol yield were detected.The results showed that Laccase-OPEFB has a good potential as hydrolysis.