Abstract:
Environmental release of dyes is an issue of health concern. Here, Stenotrophomonas sp was used for decolourization of five dyes;the present work represents screening and acclimatization of lignolytic and dye-decolorizing bacteria. The isolatesStenotrophomonas sp. was screened for lignolytic activity by guaiacol plate assay. Dye decolourization activity was carried out qualitatively on plates and quantitatively by spectrophotometry. Different parameters such as temperature and pH, were optimized for the decolourization. The bioprocess was also carried out by using Coconut husk (CH), Coconut shell (CS), Saw dust (SD), Oil palm empty fruit bunch (OPEFB), Palm kernel (PK) as growth media. In other to uncover the mechanism of decolourization, UV-Vis spectrophotometer was carried out whereas the GC-MS techniquewas utilized for the identification of degradation products. The approach revealed that the isolate Stenotrophomas sp was found to decolourize lignin-mimicking dyesby concomitantly producing ligninolytic enzymes with lignin peroxidase having the highest activity. Drastic reduction in dye degradation rate was observed beyond initial dye concentration from 25mg/L (90%), and it reaches to 70% at 100 mg/L.The optimum pH obtained for decolourizations of these dyes were at 7-8 with over 90% decolourization while the optimum temperature obtained for the decolourization of these dyes were at 35 ℃. Maximum decolourization potential was observed in presence of glucose and OPEFB as carbon source.The result also revealed that degradation is the mechanism of decolourization. The complexity and dissimilar structures of dyes might have posh the rate of decolourization by the lignolytic enzymes. Thus, the bacterial Ligninolytic enzymes can be adopted as an efficient tool for delignification of lignin and decolourization of lignin-mimicking dyes for small as well as large scale applications.
