Study Of The Industrial Process For The Separation And Purification Of Surfactin And Its Effect On Meat Preservation

Surfactin is a typical representative of Bacillus lipopeptides. It possesses the effective surface activity and a number of biological activities such as antimicrobial, antiviral, antimycoplasma, antitumor and lyse erythrocytes. Therefore, they have a great number of potential applications in health care, food processing and preservation, agriculture and environmental protection. However, the production of Surfactin by Bacillus is usually at low level. Furthermore, the downstream purification account for the higest cost of the whole process. These made it expensive and limit its application in market.In order to reduce the separation and purification costs of Surfactin, an industrial process was carried out in this study. And the application research on meat preservation of the final product produced using this process was also carried out. The main results are as following:1. A flocculation method was used to make a pretreatment of Surfactin fermentation broth. Firstly, industrial ethanol was added to the fermentation broth to the final concentration of30%, than CaCl2and Na2HPO4was added afterwards to the final content of0.5%. After blending sufficiently, the broth was stewed at room temperature for30min and filtered, the filter cake was collected and washed with water(with ethanol content of30%) for twice. The final filter cake was collected and washed with water(with ethanol content of more than50%) and the permeate was recovered and the cake was washed with water for twice. All the permeate was combined and dryed under vacuum, purity of the final powder was79.5%and the recovery rate of the process was91.9%.2. Ion exchange method was used to make a further purification of surfactin and acid precipitation was adopted to remove the NaCl of the final product. Static adsorption tests indicate that D213anion exchange resin gave the maximum adsorption capacity of497.5mg/g resin. The optimal pH was7.0and the most effective desorption reagent was0.7M NaCl. Adsorption isothermal experiment showed that the adsorption of Surfactin onto D213obeyed Langmuir model. According to the results of thermodynamics, the adsorption process was spontaneous and endothermal, and the entropy is positive. The ion-exchange kinetics for surfactin onto D213belonged to the partical diffusion control step and the apparent activation energy of the diffusion process was12.99kJ/mol. The adsorbing and eluting process were also studied by dynamic method. Under the condition of concentration of4832mg/L and flow rate of2.0mL/min, it obtained the maximum utilization rate of resin.0.7M NaC1can desorb93.1%surfactin from the resin, while there was much salt in the eluent. Acid precipitation was adopted to make a refining of the surfactin sample. The eluent was adjust to pH2.0by4.0M HC1, than made a centrifugation of the eluent and the precipitation was collected, the precipitation was washed with the equal volume of deionized water and the pH was still remained at2.0. After centrifugation, the precipitation was dissolved in deionized water and the pH was adjusted to7.0. Purity of the final surfactin solution was95.9%and the recovery rate of the ion-exchange and acid precipitation was88.1%.3. The effect of purified surfactin produced by the former process on the preservation of meat patties was also researched in this study. Surfactin with the supplementation of471.56,943.12and1886.24mg/kg meat all give a certain effect on meat preservation when stored at4℃. Compared with control, all three different supplementation of Surfactin can effectively inhibit the growth and reproduction of Lactic acid bacteria and Pseudomonas, and it is better than Nisin. Surfactin can also control the Aerobic bacterial, it can prolong the shelf-life to more than9days while the shelf-life of control group is3days only. Furthermore, Surfactin with the above supplementation can delay the rise of TVB-N, the TVB-N value of meat patties with1886.24mg/kg meat Surfactin when stored to9days was less than20mgN/100g meat, it is better than control and remained the level of fresh meat. Surfactin also had a certain effect on the TBARS, pH and chromaticity during storage. The TBARS value with the surfactin addition of1886.24mg/kg meat was much less than Nisin. Surfactin also can slow down the growth of pH value when compared with control. In addition, it can keep the color of fresh meat during storage. Sensory evaluation showed that Surfactin can keep the color stability and can reduce the putrid odor of meat patties during storage.