Enhanced application of cross-linked enzyme aggregates of lichen Dermatocarpon vellereceum released extracellular enzymes for degradation of textile dyes

Abstract

Cross-linked enzyme aggregate (CLEA) microcapsules of extracellular enzymes released by lichen Dermatocarpon vellereceum was examined for dye removal from textile wastewater. CLEA-microcapsules showed efficient decolorization of Brilliant Blue R (BBR), Direct Red 2B, Brilliant Blue GRL, Green HE4B, Red M5B, Blue 2RNL, Reactive Orange 3R, Yellow HE4G and Orange 2RX. Maximum decolorization (82%) of BBR was observed at optimum conditions (40 degrees C, pH 8, and 1.5 mM H2O2). Encapsulation efficiency (EE%) of lignin peroxidase (LiP) and manganese peroxidase (MnP) was calculated as 34.85 and 27.12%, respectively. Percent recycling efficiency (RE%) of LiP after BBR exposure was observed as 84, 72, 56 and 36% after 2nd, 3rd, 4th and 5th cycle, respectively, whereas, RE% of MnP after BBR exposure was 84, 69, 54 and 40%, respectively. Activity of LiP was retained up to 42% even after 60 days of storage, however, MnP was retained up to 36%. Central composite design of response surface methodology for CLEA-microcapsules mediated decolorization showed good correlation between predicted and observed values. BBR was cleaved to form N-ethyl-N-[(3-sulfophrnyl)methyl] pentan-3-iminium; 2-ethenyl-3-methyl-1,4-dihydronapthalene; 3-(aminomethyl)benzene-1-sulphonic acid; penta-1,4-diene and N-ethyl-2-methyl-penta-2,4-dien-1-amine, that showed significant reduction in phytotoxicity and genotoxicity. Altogether, these results suggest that CLEA-microcapsules could be utilized for efficient removal of dyes from textile effluents.