利用共培養木質醋酸菌和基因工程大腸桿菌製備多孔性細菌性纖維/黑色素複合膜及其重金屬離子吸附功能之研究

Abstract

隨著工業化的迅速發展和人類生活方式的改變，生產和消費活動導致大量污染物排放，這些污染物主要來自各種行業的工業廢水，包括電池製造、殺蟲劑生產、皮革加工、紡織業、石化產品製造和造紙等行業，其中，重金屬是工業廢水中最主要的污染物，對生態環境和人體健康造成嚴重的負面影響。在本研究中，透過共培養Komagataeibacter xylinus ATCC 700178和基因工程改造的Escherichia coli (E. coli)，將多孔狀細菌性纖維 (foaming bacterial cellulose，FBC)與黑色素 (melanin)結合，開發一款環境友善的納米複合材料，用於去除水溶液中的重金屬。本研究利用各項分析方法，包括掃描式電子顯微鏡分析、傅里葉紅外線光譜分析、X光繞射分析、熱重分析和介面電位分析，以了解FBC/melanin複合材料的物理化學特性。此外，通過批次實驗研究了重金屬在FBC/melanin複合材料上的吸附情況。FBC/melanin複合材料在pH值6時表現出對於Cu(II)的最佳吸附性能，其吸附在前20分鐘內快速上升，隨後緩慢上升並逐漸達到平衡。FBC/melanin複合材料對Cu(II)的最大吸附容量為293.59 mg/g，此結果高於其他改性細菌性纖維及其他類型的吸附劑。能量色散X射線光譜分析、傅里葉紅外線光譜分析和X射線光電子能譜分析證實了Cu(II)與FBC/melanin複合材料表面的結合，並且探討了其對Cu(II)的吸附機制。基於以上結果，FBC/melanin複合材料具有作為去除水溶液中Cu(II)的高效吸附劑的潛力。此外，本研究所提出的創新策略，即透過基因工程E. coli合成melanin並將其與多孔狀細菌性纖維透過共培養結合，這種方法不僅簡化了細菌性纖維基複合材料的製造過程並降低了成本，還成功開發出一款具有重金屬吸附能力的新型吸附劑。

The rapid advancement of industrialization and evolving human lifestyles have led to significant emissions of pollutants, predominantly originating from industrial wastewater across various sectors like battery manufacturing, pesticide production, leather processing, textiles, petrochemicals, and papermaking. Among these, heavy metals emerge as the primary pollutants in industrial wastewater, causing severe adverse effects on both ecological environments and human health. In this study, foaming bacterial cellulose (FBC) was combined with bacterial pigment, melanin nanocrystals by co-culturing Komagataeibacter xylinus ATCC 700178 with genetically engineered Escherichia coli (E. coli) to develop an environmentally friendly nanocomposite, which can effectively serve as an adsorbent for removing heavy metals from aqueous solutions. Various characterization methods, including scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetric analysis and zeta potential analysis were used to analyze the material properties of FBC/melanin composite. Batch experiments were conducted to investigate the adsorption of heavy metals. The FBC/melanin composite exhibited excellent adsorption performance at an optimized pH of 6, with rapid adsorption in the first 20 minutes followed by a gradual increase until equilibrium was reached. The maximum adsorption capacity of the FBC/melanin composite for Cu(II) was found to be 293.59 mg/g, which is higher than that of other modified BC and other types of adsorbents. The binding of heavy metals to the FBC/melanin composite surface was confirmed by energy-dispersive X-ray spectroscopy, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, and the mechanism of Cu(II) adsorption by the FBC/melanin composite was investigated. Considering these results, the FBC/melanin composite shows potential as an efficient adsorbent for the removal of Cu(II) ions from aqueous solutions. Additionally, this study provides an innovative strategy by using genetic engineered E. coli to synthesize melanin and integrating it with foaming bacterial cellulose through co-culture. This approach not only simplifies the fabrication process and reduces costs of producing BC-based composites but also produces a new bioadsorbent with heavy metal adsorption capacity.