Textile effluent characterization and evaluation of capacity color removal using the fungus Lasiodiplodia theobromae MMPI

ABSTRACT The industrial processes of textile production are characterized by the use of large volumes of water during the washing steps and fabric dyeing, resulting in effluent with enormous diversity and chemical complexity. The presence of dissolved dyes is quite noticeable and problematic, considering their recalcitrance and slow degradation kinetic. In this work, the Lasiodiplodia theobromae MMPI fungus was evaluated for their ability to removing color from effluent. The assays were performed in a bench-scale bioreactor (5 L) with an incubation time of 192 hours. The decoloring efficiency ranged from 19.52% on 24h to 91,26% on 168 h and the mycelial biomass production ranged from 1.23 g.L-1 (24 h) to 7.60 g.L-1 (168 h). Production of exopolysaccharide (EPS) also was observed, with amounts ranged from 2.84 g.L-1 (24 h) to 4.28 g.L-1 (48 h). The characterization of the effluent showed some values of control parameters outside the discharge standards required by Brazilian law, with high Chemical Oxygen Demand (COD) (659 mg.L-1) and Biochemical Oxygen Demand (BOD5) (328 mg.L-1). The toxicity analysis using the microcrustacean Artemia salina, showed that the raw effluent concentration that caused 50% mortality of organisms (LC50) was approximately 14.72% (v/v) and at the end of treatment was 4.98% (v/v). Although the fungus was not efficient in biological detoxification of the effluent, it showed promising results for its color removal capacity, demonstrating potential for use in auxiliary treatment processes of textile effluents for the color removal.

摘要
纺织品生产的工业流程在水洗工序与织物染色环节需消耗大量水资源，由此产生的印染废水具有组分多样、化学复杂性高的特点。溶解态染料的存在问题尤为突出，因其难降解性与缓慢的降解动力学特性，对环境构成显著负担。本研究针对可可毛色二孢菌（Lasiodiplodia theobromae）MMPI菌株去除印染废水中染料颜色的能力展开评估。实验采用5L台式规模生物反应器进行，培养时长为192小时。结果显示，脱色率在24小时时为19.52%，168小时时提升至91.26%；菌丝体生物量产量范围为1.23 g·L⁻¹（24小时）至7.60 g·L⁻¹（168小时）。同时检测到胞外多糖（exopolysaccharide, EPS）的产生，其产量范围为2.84 g·L⁻¹（24小时）至4.28 g·L⁻¹（48小时）。对原废水的表征分析显示，部分控制参数超出巴西法律规定的排放标准，其中化学需氧量（Chemical Oxygen Demand, COD）高达659 mg·L⁻¹，五日生化需氧量（Biochemical Oxygen Demand, BOD₅）达328 mg·L⁻¹。采用卤虫（Artemia salina）开展的毒性分析结果表明，导致受试生物50%死亡率的原废水半致死浓度（LC50）约为14.72%（体积比），经处理后的废水半致死浓度则为4.98%（体积比）。尽管该菌株未能实现废水的高效生物脱毒，但其优异的脱色能力已展现出可观的应用前景，具备应用于纺织印染废水脱色辅助处理工艺的潜力。