Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Plant Biotechnol J. 2023 Feb;21(2):302-316. doi: 10.1111/pbi.13942. Epub 2022 Oct 27.
Microfibres (diameter <5 mm) and textile dyes released from textile industries are ubiquitous, cause environmental pollution, and harm aquatic flora, fauna, animals and human life. Therefore, enzymatic abatement of microfibre pollution and textile dye detoxification is essential. Microbial enzymes for such application present major challenges of scale and affordability to clean up large scale pollution. Therefore, enzymes required for the biodegradation of microfibres and indigo dye were expressed in transplastomic tobacco plants through chloroplast genetic engineering. Integration of laccase and lignin peroxidase genes into the tobacco chloroplast genomes and homoplasmy was confirmed by Southern blots. Decolorization (up to 86%) of samples containing indigo dye (100 mg/L) was obtained using cp-laccase (0.5% plant enzyme powder). Significant (8-fold) reduction in commercial microbial cellulase cocktail was achieved in pretreated cotton fibre hydrolysis by supplementing cost effective cellulases (endoglucanases, ß-glucosidases) and accessory enzymes (swollenin, xylanase, lipase) and ligninases (laccase lignin peroxidase) expressed in chloroplasts. Microfibre hydrolysis using cocktail of Cp-cellulases and Cp-accessory enzymes along with minimal dose (0.25% and 0.5%) of commercial cellulase blend (Ctec2) showed 88%-89% of sugar release from pretreated cotton and microfibres. Cp-ligninases, Cp-cellulases and Cp-accessory enzymes were stable in freeze dried leaves up to 15 and 36 months respectively at room temperature, when protected from light. Use of plant powder for decolorization or hydrolysis eliminated the need for preservatives, purification or concentration or cold chain. Evidently, abatement of microfibre pollution and textile dye detoxification using Cp-enzymes is a novel and cost-effective approach to prevent their environmental pollution.
微纤维（直径 <5 毫米）和纺织工业释放的纺织染料无处不在，造成环境污染，危害水生植物、动物和人类生命。因此，消除微纤维污染和纺织染料解毒至关重要。用于此类应用的微生物酶存在大规模应用的主要挑战，即难以负担清理大规模污染的费用。因此，通过叶绿体遗传工程，在转基因烟草植物中表达了用于生物降解微纤维和靛蓝染料的酶。通过 Southern blot 证实了漆酶和木质素过氧化物酶基因整合到烟草叶绿体基因组中和同型性。使用 cp-漆酶（0.5%植物酶粉）可获得含有靛蓝染料（100mg/L）的样品的脱色（高达 86%）。通过补充具有成本效益的纤维素酶（内切葡聚糖酶、β-葡萄糖苷酶）和辅助酶（膨胀素、木聚糖酶、脂肪酶）以及在叶绿体中表达的木质素酶（漆酶木质素过氧化物酶），预处理棉纤维水解中商业微生物纤维素酶混合物的用量显著减少（8 倍）。使用 Cp-纤维素酶和 Cp-辅助酶的混合物以及最小剂量（0.25%和 0.5%）的商业纤维素酶混合物（Ctec2）进行微纤维水解，可从预处理棉和微纤维中释放出 88%-89%的糖。Cp-木质素酶、Cp-纤维素酶和 Cp-辅助酶在室温下保存在冻干叶片中，分别可稳定 15 和 36 个月，避光保存。使用植物粉末进行脱色或水解可消除对防腐剂、纯化或浓缩或冷链的需求。显然，使用 Cp-酶消除微纤维污染和纺织染料解毒是防止其环境污染的一种新颖且具有成本效益的方法。
