Decolorization of remazol brilliant blue R with laccase from Lentinus crinitus grown in agro-industrial by-products

ABSTRACT Lentinus crinitus is a white-rot fungus that produces laccase, an enzyme used for dye decolorization. Enzyme production depends on cultivation conditions, mainly agro-industrial by-products. We aimed to produce laccase from Lentinus crinitus with agro-industrial by-products for dye decolorization. Culture medium had coffee husk (CH) or citric pulp pellet (CP) and different nitrogen sources (urea, yeast extract, ammonium sulfate and sodium nitrate) at concentrations of 0, 0.7, 1.4, 2.8, 5.6 and 11.2 g/L. Enzymatic extract was used in the decolorization of remazol brilliant blue R. CH medium promoted greater laccase production than CP in all evaluated conditions. Urea provided the greatest laccase production for CH (37280 U/L) as well as for CP (34107 U/L). In CH medium, laccase activity was suppressed when carbon-to-nitrogen ratio changed from 4.5 to 1.56, but the other nitrogen concentrations did not affect laccase activity. For CP medium, reduction in carbon-to-nitrogen ratio from 6 to 1.76 increased laccase activity in 17%. The peak of laccase activity in CH medium occurred on the 11th day (41246 U/L) and in CP medium on the 12th day (32660 U/L). The maximum decolorization within 24 h was observed with CP enzymatic extract (74%) and with CH extract (76%).

摘要：毛盖香菇（Lentinus crinitus）是一种可分泌漆酶（laccase）的白腐真菌，该酶可应用于染料脱色反应。酶的合成受培养条件调控，农业工业副产物为其主要碳源底物。本研究旨在利用农业工业副产物作为碳源，通过毛盖香菇生产漆酶并用于染料脱色。实验培养基以咖啡壳（CH）或柠檬酸浆颗粒（CP）为碳源，并添加浓度梯度为0、0.7、1.4、2.8、5.6及11.2 g/L的四种氮源：尿素、酵母提取物、硫酸铵与硝酸钠。将制备得到的粗酶提取物用于雷玛唑亮蓝R（remazol brilliant blue R）的脱色实验。在所有测试条件下，咖啡壳培养基的漆酶产量均高于柠檬酸浆颗粒培养基。尿素为两类培养基的最优氮源，其中咖啡壳培养基的漆酶产量可达37280 U/L，柠檬酸浆颗粒培养基为34107 U/L。在咖啡壳培养基中，当碳氮比从4.5降至1.56时，漆酶活性受到抑制，其余氮源浓度对漆酶活性无显著影响；而在柠檬酸浆颗粒培养基中，碳氮比从6降至1.76时，漆酶活性提升17%。咖啡壳培养基的漆酶活性峰值出现在培养第11天（41246 U/L），柠檬酸浆颗粒培养基的峰值则出现在第12天（32660 U/L）。两类粗酶提取物在24小时内的最高脱色率分别为：柠檬酸浆颗粒提取物74%，咖啡壳提取物76%。