COMPARATIVE BIODECOLORIZATION AND DETOXIFICATION OF SYNTHETIC DYES BY INDIGENOUS BATIK WASTEWATER BACTERIA

Abstract

The Malaysian batik industry, although economically important, generates dye-laden wastewater that poses significant environmental risks due to the lack of sufficient treatment facilities. Conventional remediation methods are often costly, produce secondary pollutants, or require advanced infrastructure, making them impractical for small-scale industries. Utilizing native bacterial strains offers a promising, eco-friendly alternative, however, this approach remains underexplored for batik wastewater. This study evaluated the decolorization potential of two indigenous isolates, KR1 and KR2, obtained from batik wastewater, against four commonly used dyes: Congo Red (CR), Crystal Violet (CV), Disperse Yellow (DY), and Methylene Blue (MB). Experiments were performed under static and shaking conditions at 37°C, unadjusted pH, 250 mg/L dye concentration, and 24 h incubation, with static conditions consistently outperforming shaking. Strain KR1 exhibited superior performance, removing 49% of CR, 90% of CV, 50% of DY, 51% of MB and 71% batik wastewater, whereas strain KR2 achieved only 23%, 35%, 20%, 23% and 23%, respectively. Ultraviolet-visible analysis confirmed CV degradation by strain KR1, indicated by the disappearance of peaks at 590, 330, and 260 nm and the emergence of new peaks at 220 and 360 nm, suggesting simpler metabolites. Phytotoxicity tests using Vigna radiata showed 100% germination and healthy seedling growth with strain KR1-treated CV, while untreated CV almost completely inhibited germination. These findings position strain KR1 as an efficient and sustainable bioremediation agent for batik wastewater, contributing to global sustainability goals through improved water quality management and resource recovery for agricultural reuse.