以柑橘果渣为主要原料生产细菌纤维素的研究

目的:拓宽细菌纤维素(BC)生产的原料来源,明确柑橘渣水对汉逊氏葡糖酸醋杆菌CIs51发酵产BC的影响。方法:以筛选自酸败柑橘果实的汉逊氏葡糖酸醋杆菌CIs51为发酵菌株,以柑橘果渣为主要原料,用扫描电镜观察其微结构,研究果渣预处理工艺、营养源、生长因子等对BC产量及微结构的影响。结果:柑橘果渣与水以1:8(W/V)的比例混合打浆,以150U/mL的果胶酶复配100U/mL纤维素酶,45℃水解2h;过滤后进行酵母前发酵工艺;选择蔗糖为碳源,添加量30g/L,(NH4)2SO4为氮源,添加量3g/L,酵母粉和柠檬酸的添加量分别为5g/L和1g/L。在此优化培养基中CIs51的产量达7.23g/L,明显高于其在HS培养基、柑橘渣水改良HS(CMHS)培养基中的产量(依次为4.02g/L及6.57g/L)。结论:柑橘渣水能够显著提高CIs51的BC产量,所得BC膜呈半透明质地,柔韧性好,具有替代椰子水进行工业化生产的前景。

Production of Bacterial Cellulose in the Culture Medium Based on Citrus Dregs

Objective:To broaden raw material source of bacterial cellulose(BC) production,and determine the effect of citrus dregs on the production of BC by Gluconacetobacter hansenii CIs51.Method:Gluconacetobacter hansenii CIs51 from rotten citrus fruit is screened as fermentation strain and citrus dregs is chosen as the main raw material,scanning electron microscopy is used to investigate BC microstructure.Effects of pro-treatment of citrus dregs,nutrient source,growth factors on BC yield and microstructure of CIs51 are researched.Results:Citrus dregs are mixed with distilled water as the ratio of 1:8(W/W),then are hydrolyzed with pectinase of 150 U/mL and cellulase of 100 U/mL at 45 ℃ for 2 h;The resulting filtrate is fermented by active dry wine yeast.Sucrose is chosen as carbon source and ammonium sulphate as nitrogen source,with their concentrations of 30 g/L and 3 g/L respectively.Concentrations of yeast extract and citric acid as the growth factors of CIs51 are determined as 5 g/L and 1 g/L,respectively.The BC yield of CIs51 in this optimized medium reaches to 7.23 g/L,which is much higher than those in HS medium and citrus dregs filtrate modified HS(CMHS) medium(4.02 g/L and 6.57 g/L,correspondingly).Conclusion:Citrus dregs waste could stimulate BC production by strain CIs51 efficiently,BC film obtained has translucent texture and nice flexibility,which appeares to have potential for citrus dregs in industry applications of BC manufacture instead of coconut juice.