[关键词]
[摘要]
为提高餐厨垃圾水解液发酵产油脂量,探究其发酵生产特征和影响因素,以Saccharomyces cerevisiae As2.516为供试菌株,以初始餐厨垃圾水解液加入量90%(V/V)、搅拌速率180 r/min、通气量2.5 L/min、发酵周期10 d为基础发酵条件进行1 L发酵罐发酵。实验结果表明发酵过程受初始pH值、温度、接种生物量、还原糖含量及无机盐、金属离子浓度影响。其中最适宜初始培养条件为:pH值6、温度30 ℃、接种量10%,该条件下生物量、油脂产量及产物转化率最大。以实验最适宜培养条件为基础发酵条件时,S. cerevisiae发酵第7d油脂产量最高,为4.26 g/L,生物量12.95 g/L,油脂产率32.9%。经气相色谱分析发酵所得脂肪酸主要由C16及C18脂肪酸组成,其中不饱和脂肪酸占72.09%。餐厨垃圾水解液中无机盐离子含量丰富,外加钾、镁、锰等金属离子抑制菌体生长并影响油脂合成,除微量CuSO4?5H2O(1×10-4 g/L)外,无需添加其它无机盐。S. cerevisiae利用餐厨垃圾水解底物具有谱宽和抗逆性。
[Key word]
[Abstract]
To increase microbial oil production by fermentation from food waste hydrolysates and to study the characteristics of fermentation production and the factors that influence it, Saccharomyces cerevisiae As2.516 was used as a test strain. Fermentation was conducted in a 1-L fermentor, and the fermentation conditions were as follows: initial amount of food waste hydrolysates, 90% (V/V); agitation speed, 180 r/min; aeration rate, 2.5 L/min; fermentation cycle, 10 d. The fermentation process was affected by the initial pH value, temperature, inoculation biomass, content of reducing sugar, and concentrations of inorganic salts and metal ions. The optimal culture conditions were as follows: pH value, 6; temperature, 30 ℃; inoculum size, 10%. Under these conditions, the maximum biomass, oil production, and product conversion rate were observed. On day 7 of the fermentation by S. cerevisiae, the highest oil yield was attained (4.26 g/L), and the biomass and oil production rate were 12.95 g/L and 32.9%, respectively. The gas chromatography analysis showed that C16 and C18 fatty acids were the main components of the fatty acids produced by fermentation, and unsaturated fatty acids accounted for 72.09%. Inorganic salts were abundant in the food waste hydrolysates; additional potassium, magnesium, manganese, and other ions could inhibit bacterial growth and affect oil production. Therefore, except for a trace amount of CuSO4?5H2O (1 × 10-4 g/L), it was not necessary to add additional inorganic salts. S. cerevisiae , which used food waste hydrolysates, was characterized as broad-spectrum and stress tolerant.
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[基金项目]
国家自然科学基金资助项目(51309032);“港口、海岸及近海工程”省级重点学科开放课题