Fermentation Preparation Of Nano Prodigalin And Research On Antibacterial Dyeing Of Fabrics

As an important component of natural pigments,microbial pigments have attracted wide attention in recent years due to their advantages of short production cycles,large output,being free from seasonality,climate and geographical constraints,easy to control conditions,and rich species.As a main component of the microbial pigments,microbial intracellular pigment with poor water-solubility needs to be extracted from the bacterial cells by organic solvent before it is used as the textile dye.At the same time,a certain amount of organic solvent needs to be added when preparing the dye solution.The use of organic solvent increases the cost of pigment extraction and fabric dyeing,and runs counter to the green and environmental protection concept of natural dyes.The vast majority of microbial dyes have low affinity with cellulose and generally use mordant dyeing for cotton fabrics.Traditional mordant contains heavy metal ions,and many of them are listed in banned list of ecological textiles.At the same time,the complexation occurs between mordant and some active groups of the microbial dye,which destroys the valuable functionality of microbial dyestuffs.In view of the above two issues,this article takes prodigiosins which is a kind of intracellular pigment with good thermostability as the research object and carry out the following work:1.Nonionic surfactant Tween 80 was added into the fermentation broth of Serratia marcescens,and for the first time a prodigiosins nanosuspension with an average particle size of 184.3 nm was prepared using a surfactant fermentation system,which achieved the direct extraction of intracellular pigment in fermentation process.The prodigiosins nanosuspension could be directly used as dye solution for fabrics dyeing.The preparation of the prodigiosins dye liquor by this method effectually avoided the use of organic solvents and simplified the preparation process of dye liquid.2.A method for cotton fabric dyeing and fixing with nano prodigiosins based on solubilization mechanism of solvent was designed.By adding a certain percentage of ethanol to the dyeing liquor,direct dyeing of the cotton fabric with prodigiosins was achieved without using mordants.The results showed that when the ethanol content in the dye solution was 25%(V/V),the dyeing temperature was 90 ?,and the dyeing time was 75 min,the color obtained was the deepest.The dyed cotton fabric had good color fastness to rubbing,soaping and perspiration.In addition,the dyed cotton fabric inherited the antibacterial activity of prodigiosins.The antibacterial rate against Staphylococcus aureus reached 94.1%,and it was 5 1.4%against E.coli.3.A method for cotton fabric dyeing and fixing with nano prodigiosins based on pH control mechanism was designed.Direct dyeing of cotton fabrics with prodigiosins without the utilization of mordants and organic solvents was achieved.The results showed that the K/S value of the cotton fabric reached maximum when pH value of the prodigiosins nanosuspension dye liqour was 3,the dyeing temperature was 90?,and the dyeing time was 60 min.Tensile breaking strength test and XRD analysis showed that the dyed cotton fabric was not damaged obviously under optimal dyeing condition.Antibacterial results showed that the antibacterial activity of cotton fabrics was positively correlated with the color depth of fabric.Under the optimal dyeing condition,the antibacterial rate of cotton fabric against Staphylococcus aureus reached 99.2%,and the antibacterial rate against Escherichia coli reached 85.5%.In addition,cell compatibility experiments showed that the dyed cotton fabric were not potentially cytotoxic,and the growth of L929 cells was almost the same as that of undyed fabric.4.Dyeing and fixing polyester and silk fabrics with prodigiosins were achieved based on nanosuspension system.The optimal temperature for the polyester dyeing was 110 ? and the time was 30 min.The pH value of the dyeing solution had a significant influence on the color and antibacterial properties of polyester fabrics.With the increase of the dye liquor pH,the color of the polyester fabric showed a change from purple to red.When the pH of dye solution was higher than the isoelectric point of prodigiosin,the polyester fabric no longer exhibited antibacterial activity.The optimal dyeing temperature and time for silk fabrics were 80 ? and 30 min,respectively.Due to the different electrostatic forces between silk fibers and prodigiosins molecules at different pH conditions,the dyeing solution pH had obvious effect on dye uptake and fabric color depth.Since protein molecules in silk fabrics provided nutrients for bacteria,compared with cotton fabrics and polyester fabrics,the dyed silk fabrics had a significantly lower bacterial inhibition rate against E.coli.The use of prodigiosins nanosuspension for dyeing polyester and silk fabrics required no organic solvents and was environmentally friendly.