Electron Mediator Enhanced Bioreduction Dyeing Of Indigo

Indigo is one of the dyes with the longest history in China and occupies an important position in the traditional dyeing and weaving culture.Due to the environmental problems in the dyeing process of the textile industry,the textile industry is increasingly interested in studying green and clean methods.Therefore,as green manufacturing has become the development direction of the manufacturing industry today,The realization of innocuous and sustainable dyeing processing raw materials has positive significance for the preparation of ecological textiles.In this study,a controllable whole-cell reduction system of yeast was constructed by referring to the traditional dyeing method of reducing indigo with rice wine(yeast),and the concept of electronic medium was introduced to enhance the whole-cell reduction system.From the selected yeast strain as the starting point,by exploring its endogenous electron mediator metabolism,riboflavin(vitamin B2)was selected as an endogenous electron mediator that is milder to the normal growth and metabolism of yeast strains,and the mediating effect is also selected.Three stronger exogenous electron mediators strengthen the whole cell reduction system.Through the analysis of the p H,conductivity,potential and the content of indigo leuco in the reduction system during its mediation process,the K/S value,levelness and color fastness of the dyed fabric are used as evaluation indicators to obtain Alizarin and 1,8-dihydroxyanthraquinone have a strong mediating effect,and the K/S values reached14.3 and 11.7 respectively before the process was optimized.The mediating effect of riboflavin and 2-hydroxy-1,4-naphthoquinone is slightly weak.Before the process was optimized,the K/S values reached 6.1 and 5.7,respectively.The dyeing process of riboflavin and alizarin was optimized by response surface.After optimization,the K/S of fabric after alizarin-mediated whole-cell reduction dyeing reached 21.42,compared with the biological reduction system with no electronic medium,the K/S of dyed fabric has improved 12.And it was only 0.3 difference from the K/S value of fabric dyed by traditional soluene chemical reduction method.The electron mediator was tested by Fourier infrared spectroscopy to explore the differences in the mediation of electron mediators with different structures and physical and chemical properties.Scanning analysis of yeasts by SEM and TEM and semipermeable membrane experiments verified that the whole-cell reduction system under electron mediator-mediated conditions includes three electron transfer pathways: direct contact transfer,nanowire transfer,and indirect electron transfer via electron mediator during the process of reducing indigo dye.Simultaneously,based on the inspiration of the semipermeable membrane experiment in the process of exploring the mechanism,an indigo-sodium alginate composite microsphere was prepared,and the composite microsphere was used instead of the indigo dye to dye the fabric,achieving a more uniform dyeing and saving dye effect.This research constructs an electron mediator-mediated whole-cell reduction method to elevate spontaneous and random biological phenomena to a controllable and efficient biological process.And this process avoids the use of strong reducing agent and reduces pollution which realizes the efficient and safe clean dyeing of indigo,and provides new ideas for the sustainable and clean production of dyeing processing.