Use Of Desizing Wastewater For Production Of Lipopeptide And Its Application In Dyeing & Finishing Technology

Lipopeptides have gained more and more attention due to their excellent surface activities, biodegradability, low toxicity, and environmentally friendly. Lipopeptides exhibited potential applications in cosmetic, environmental fields, biomedicine, food and textile industry. However, its applications have been restricted to a great extent because of their low yields and complex purification procedures and high costs. In this dissertation, we reported the production of lipopeptides using desizing wastewater as alternative carbon source by Bacillus subtilis HSO121, and discussed the applications of crude lipopeptides in Dyeing & Finishing technology after simplifying purification procedures.In this paper, we used the commercial starch as carbon source. Single factor test and orthogonal experiment were used to optimize the production of lipopeptides by Bacillus subtilis HSO121. The biomass, lipopeptides yields and reduced surface tension values were selected as evaluating parameters. Grown in the optimized medium, lipopeptides yields improved from 0.67 g/L to 1.24 g/L.The effects of main composition in the desizing wastewater on lipopeptides yields were investigated. The results demonstrated that the concentration of NaCl less than 10g/l and the concentration of penetrant JFC less than 0.1 g/l in medium could contribute to growth and metabolism of bacteria, a small amount of PVA had no significant effect on growth and metabolism of bacteria, but PVA should less than 30% in sizing agent.Bacillus subtilis HSO121 grew well in the desizing wastewater medium, which prepared by pretreated desizing wastewater according to the optimized medium, the yields of lipopeptides attained 1.03 g/L. Moreover, the Chemical Oxygen Demand of the desizing wastewater after cultivation reduced by half compared with before cultivation, decreased from 41360 mg/L to 22880 mg/L.The lipopeptides were separated and extracted from the desizing wastewater medium after cultivation, and characterized by thin layer chromatography (TLC) on silica gel and infrared ray (IR) analysis. The charged detection for lipopeptides was anionic-surfactant. Emulsification activity of the lipopeptides from Bacillus subtilis HSO121 was measured with water-immiscible substrates. The results show that the lipopeptides had high emulsification activity and emulsification stability against liquid paraffin. After 24 hours the emulsification index was 83%. The CMC of the lipopeptides was approximately 50 mg/L, and the lipopeptides reduced the surface tension of the water from 72 to 28.53mN/m.In order to reduce the cost used, the crude lipopeptides were prepared by discoloring. The crude lipopeptides as soaping agents in soaping process were investigated. The test sample was poplin dyed with partially hydrolyzed reactive red 3BS, reactive yellow 3RS and reactive blue BRF. The optimal soaping process was obtained: pH=9, 0.05g/L of lipopeptides, at 75°C. Regardless of dyeing by partially hydrolyzed reactive red 3BS, reactive yellow 3RS or reactive blue BRF, the results of soaping with lipopeptides were better than traditional soaping process. Compared with traditional soaping process, lipopeptides soaping showed higher efficient, higher colorfastness, more energy-efficient and more environmentally friendly.The crude Lipopeptides as fabric antibacterial agents were investigated. In the agar diffusion plate method, the fabric after antibacterial finish showed a large and clear inhibition zone on solid agar medium against E. coli and S. aureus, the width of the inhibition zone was 2.1 mm and 1.4 mm respectively. It indicated that the fabric after antibacterial finish was leaching type antibacterial fabric, and had good antibacterial effect. In the shake flask method, the finished fabric showed over 84.02% bacterial reduction against E. coli, and over 82.17% bacterial reduction against S. aureus. It is well recognized that lipopeptides has good antimicrobial activity. The crude Lipopeptides as fabric softener were investigated. The bending length of wool fabric before softening finishes was 18.9 mm and after softening finishes was 13.7 mm. The results showed that lipopeptides as softener improved performance of wool soft.