腐乳发酵过程中酶活力和化学组分变化研究

通过发酵罐培养高大毛霉MHC-7,并对腐乳发酵过程中酶活力及化学组分变化规律进行研究。结果表明：MHC-7 在发酵罐扩大培养条件下,最佳发酵时间是30h。蛋白酶、α- 淀粉酶、α- 半乳糖苷酶、谷氨酰胺酶、纤维素酶、脂肪酶、糖化酶和果胶酶活力在豆坯上产酶的峰值时间分别是48、36、48、48、66、36、30 和72h;在腐乳后发酵中除谷氨酰胺酶呈上升趋势,其它几种酶都呈下降趋势,粗蛋白、粗脂肪和还原糖含量随着发酵时间的延长不断下降,氨基态氮、游离脂肪酸和总酸含量不断增加;当达到谷氨酰胺酶≥ 86.3U/g、总酸≥ 1.0%、氨基态氮≥ 0.45%、还原糖≤ 1.1% 及黏度≤ 2 × 105mPa·s 时可以作为为判断腐乳成熟的标准。     

南极假丝酵母产脂肪酶在15 L发酵罐中培养条件的研究

对15 L发酵罐中南极假丝酵母(C.antarctica DSM3855)的发酵工艺条件进行了研究,确定了最适的产酶工艺条件:搅拌速度为300 r·min-1,通气量为10 L·min-1,接种量为10%,添加GPE作为消泡剂.在此培养条件下,培养54 h产酶达到高峰值,最高酶活力达到19.3 U·mL-1.     

Statistical analysis of effects of experimental variables on mass transfer coefficient in a novel hybrid bubble column using Box–Behnken design

Statistical analysis of effects of experimental variables on volumetric mass transfer coefficient in a novel hybrid rotating and reciprocating perforated plate bubble column is studied. The novel bubble column is designed indigenously using bevel gear arrangement. Agitation level, superficial gas velocity, superficial liquid velocity, perforation diameter and plate spacing are the experimental variables. Air–sodium sulphite solution system is used in this investigation. The Box–Behnken design in response surface methodology is employed for statistical analysis. The relationship between experimental variables and the desired response of volumetric mass transfer coefficient is established for this novel hybrid column. The linear, quadratic and interactive effects of experimental variables are found to be significant on the desired response of volumetric mass transfer coefficient. Results show that the data adequately fit into the second‐order polynomial model. An F‐test and P‐value show the significance of parameters on volumetric mass transfer coefficient. © 2012 Canadian Society for Chemical Engineering     

基于混合微分进化算法的生化过程动态参数估计(英文)

Determination of the optimal model parameters for biochemical systems is a time consuming iterative process. In this study, a novel hybrid differential evolution (DE) algorithm based on the differential evolution technique and a local search strategy is developed for solving kinetic parameter estimation problems. By combining the merits of DE with Gauss-Newton method, the proposed hybrid approach employs a DE algorithm for identifying promising regions of the solution space followed by use of Gauss-Newton method to determine the optimum in the identified regions. Some well-known benchmark estimation problems are utilized to test the efficiency and the robustness of the proposed algorithm compared to other methods in literature. The comparison indicates that the present hybrid algorithm outperforms other estimation techniques in terms of the global searching ability and the convergence speed. Additionally, the estimation of kinetic model parameters for a feed batch fermentor is carried out to test the applicability of the proposed algorithm. The result suggests that the method can be used to estimate suitable values of model parameters for a complex mathematical model.     

自吸式发酵罐用于酵母生产工艺的研究进展

自吸式发酵罐的研究始于20世纪50年代,最初应用于醋酸的生产,60年代尝试运用于酵母生产,相对于鼓泡式发酵罐和传统机械搅拌式发酵罐,自吸式发酵罐具有发酵过程中传质混合好、溶氧量高、耗电量小、体积生产率高、占用面积少等优点。本文对自吸式发酵罐应用于酵母生产工艺,发酵罐的结构,通气原理以及相对于其他发酵罐的优缺点等方面进行了综述。     

Scale-up methodologies for Escherichia coli and yeast fermentation processes

Scale-up techniques from the literature have been compiled and reviewed for applicability to Escherichia coli and yeast processes. The consistency of design and operating parameters for the pilot scale vessels in an existing fermentation pilot plant, ranging in nominal volume from 100 l to 19,000 l, was established and compared favorably with approaches found in the literature. Differences were noted as a function of parameters such as fermentor scale, vessel geometry, agitator type/size and ungassed/gassed power input. Further analysis was conducted using actual fermentation data for historical and recent development processes collected over a 10-year-period, focussing on operating conditions at peak culture oxygen uptake rates. Scale-up estimates were performed based on geometric similarity, agitator tip speed, gassed power per unit volume and mixing time. Generally, scale-up calculations from the 280 l scale were most similar to the parameters of installed equipment. Scale-up from the 30 l laboratory scale typically underpredicted parameters with scale-up from the 280 l scale being most appropriate. The 19,000 l fermentor installation was notably different in geometric similarity from the 280 l-1900 l scales since its design was meant to accommodate a wide range of operating volumes. Analysis of historical and recent processing performance was conducted for single cell bacterial or yeast fermentations which challenged peak operating conditions of the fermentors. Identification of key issues associated with scale-up for these specific pilot plant vessels was believed to be critical to efficient process development, clinical material production, and expected process transfer to a manufacturing facility.     

自吸式液体醋酸发酵罐密封件降温系统的改造

该文简要叙述了自吸式醋酸发酵罐密封件系统的安装步骤和要求，重点叙述运用动力学原理对密封件降温系统改造的设计。     

A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT,ALBERTA PART 1: WHOLE OIL SAMPLES.

ABSTRACT

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. Relative to a core sample, the fireflood-produced oils exhibited a significant reduction in density and viscosity which began early in the production cycle. This behaviour was correlated with a marked increase in material boiling in the naphtha and middle distillate ranges and a concomitant decrease in the residue cut. The sulfur and nitrogen contents in the produced oils decreased relative to the core sample. A reduction in the acid number of the produced oil samples was coupled with an increase in the oxygen content as the firefiood proceeded. The relationship between these changes and the dynamics of the in situ combustion process are discussed.     

生产在线留贮啤酒酵母用种的方法

在线留贮啤酒酵母用种是啤酒生产的技术环节之一 ,其内涵因厂家而异 ,该文比较详细的阐述了适宜中小型企业应用的生产在线留贮啤酒酵母用种的方法。