In this work, the production and downstream processing of gellan gum obtained from milk skin residue (MSR) as a carbon source was investigated. The different medium variables, namely shaking speed, inoculum size, and nitrogen source, on gellan gum production were studied. The suitable medium variables were found to be shaking speed (150 rpm); inoculum size (5% v/v), and nitrogen source (yeast extract, YE). The production of gellan gum was compared for various carbon sources, namely fructose, sucrose, glucose, lactose, and MSR. In order to obtain higher gellan gum concentration, response surface methodology was employed for optimizing MSR to glucose ratio, initial pH, and yeast extract concentration. The maximum gellan gum concentration of 8.98 ± 0.42 g/L was obtained at the following optimum conditions: ratio of MSR and glucose = 1:0.743, initial pH (7.5), and yeast extract concentration 8 g/L. The concentration of gellan gum was increased by 2.73-fold than un-optimized medium. The various factors influencing the recovery of gellan gum, namely screening of solvents, ratio of solvent to supernatant (v/v), and incubation time for precipitation, were also studied. The purified gellan gum was characterized by thermogravimetric analysis (TGA/DSC), Fourier transform infrared spectroscopy, scanning electron microscope, and X-ray diffraction analysis.

在这项工作中，研究了由牛奶皮肤残渣（MSR）作为碳源获得的吉兰糖胶的生产和下游加工。研究了结冷胶生产中不同的培养基变量，即摇动速度，接种量和氮源。发现合适的介质变量是摇动速度（150 rpm）；接种量（5％v / v）和氮源（酵母提取物，YE）。比较了吉兰糖胶的生产中各种碳源，即果糖，蔗糖，葡萄糖，乳糖和MSR。为了获得更高的结冷胶浓度，采用响应表面方法优化了MSR与葡萄糖的比率，初始pH值和酵母提取物的浓度。在以下最佳条件下获得的最大吉兰糖胶浓度为8.98±0.42 g / L：MSR与葡萄糖之比= 1：0.743，初始pH（7.5），酵母提取物浓度8 g / L。吉兰糖胶的浓度比未优化的培养基增加了2.73倍。还研究了影响结冷胶回收的各种因素，即溶剂的筛选，溶剂与上清液的比率（v / v）以及沉淀的孵育时间。纯化的吉兰糖胶通过热重分析（TGA / DSC），傅立叶变换红外光谱，扫描电子显微镜和X射线衍射分析进行表征。