微量营养素对玉米酵母流加培养的影响

文中研究了微量营养素的不同添加量对玉米酵母流加培养过程中糖液流加速率、溶氧量、酵母细胞浓度、酵母细胞生长率的变化,得出微量营养素的添加量为CaCl2 28.8mg/L,FeSO4 14.4mg/L,盐酸硫氨4.8mg/L,生物素0.12mg/L,D-泛酸钙6.4mg/L,肌醇120mg/L,玉米酵母细胞的产率提高了80.9%。

溶氧量对以玉米培养基流加培养生产酵母的影响

本文通过以玉米为培养基流加培养生产酵母过程中,用控制通氧的方法研究溶氧量对酵母细胞浓度和酵母细胞生长速率的影响,得出通氧量的控制与酵母生长的关系。结论为:溶氧量达到50%的时候,酵母细胞产率最大,达到38%。

响应面法优化玉米生产酵母培养基

利用响应面法优化了玉米生产酵母的培养基,最佳培养基组成为:硫酸铵3.1128g/L,磷酸氢二钾1.51g/L,硫酸镁0.0976g/L,其最佳质量比(NH4)2SO4∶KH2PO4∶MgSO4·7H2O=2∶1∶0.1。且在此条件下进行发酵试验,酵母的细胞浓度达到了38.103g/L,比优化前提高了14.3%。

玉米酵母包埋剂的研究

通过对比β-环糊精、海藻酸钙、山梨醇酐单硬脂酸酯(SMS)、分子蒸馏单甘酯、分子蒸馏三聚甘油单酯等包埋剂包埋效果,确定了以SMS作为玉米酵母的保护剂,且其最优添加量为1%,最终酵母细胞达到了80%以上。

营养盐对玉米粉生产酵母的影响

以玉米糖液为碳源生产酵母时,需要补充大量营养盐。文中通过摇瓶试验,采用响应面法优化了添加营养盐生产玉米酵母的工艺。结果表明,营养盐的添加量为(NH4)2SO42.1127g/L,KH2PO41.51g/L,MgSO4.7H2O 0.0976g/L,且氮磷比对培养基的影响作用较大,其最佳质量比为4∶3。

流加培养生产玉米酵母工艺研究

通过研究以玉米粉作为培养基流加培养生产酵母的工艺,得出:流加培养生产玉米酵母最佳接种量10%,溶氧量为50%,同时添加营养盐和微量营养素,最适宜酵母细胞的生长温度为30℃,流加培养的最佳时间是20～22h,采用植物油为消泡剂,发酵过程中减少CO2,鲜酵母的产量达到了99.8g/L。

酵母干燥过程中几种包埋剂的比较

以玉米为原料生产酵母,分析比较3种酵母包埋剂的效果,通过测定每克活性干酵母的细胞总数、活细胞率及发酵力,最终确定了以脱水山梨醇单硬脂酸甘油酯作为酵母的保护剂,其最优添加量为1%(酵母干重),能够使其用于面食的发酵。

Brewing of low-alcoholic drink from corncobs via yeast-cellulase synchronous fermentation process

The present work focuses on the influence of various parameters, i.e., the dosage of cellulase, the inoculum concentration of yeast, the fermentation temperature and the fermentation time, on the alcohol content and sensory evaluation of the low-alcoholic health drink produced from corncob in a yeast-cellulase synchronous fermentation process. The fermentation was performed by inoculating the seed solution (containing corncob powder and yeast) and cellulase into the synchronous saccharification fermentation medium. Single-factor experiments and orthogonal experiments were performed, and the optimal processing conditions were obtained based on the characterizations of alcohol content and sensory evaluation. The results show that the alcohol content and sensory evaluation of the drink can reach 6.1 vol.% and 92, respectively, when the dosage of cellulase, inoculum concentration of yeast, the fermentation temperature and the fermentation time are 15 U/g, 7%, 32℃ and 84 h, respectively.

Corncobs as Substrate for Oleaginous Yeast-Pretreatment via Steam Explosion and Hydrolysis

Corn cobs are a promising lignocellulosic substrate for the production of biofuels like bioethanol via conventional yeast or biodiesel via oleaginous yeast. Pretreatment of the substrate is essential for further hydrolysis and fermentation steps. This study focused on the steam explosion method as pretreatment. Therefore, different steam explosion severities were evaluated. The content of glucan, xylan and Klason lignin was examined. Xylan degraded with increasing severity from 412.7 g·kg-1 （untreated） to a minimum of 127.3 g-kg1 dry matter （190 ℃/30 min）. Glucan concentrations increased from 315.1 g·kg1 （untreated） to a maximum of 371.6 g·kg-1 dry matter （200 ℃/20 min）. For soluble lignin, an increase could be observed at rising severity, from 145.3 g·kg-l （untreated） to a maximum of 214.9 g·kg-1 dry matter （190 ℃/30 min）. Furthermore, the mass recovery was calculated. At harsher pretreatment conditions, a significant mass loss was observed, estimated by the ash content in the recovered dry matter. The lowest recovery rate was observed for SF = 4.13 （190 ℃/30 min） with 68.39%. The produced inhibitors were evaluated.