Biohydrogen production with anaerobic sludge immobilized by granular activated carbon in a continuous stirred-tank

A continuous stirred-tank reactor （CSTR） process with granular activated carbon （GAC） was developed for fermentation hydrogen production from molasses-containing wastewater by mixed microbial cultures. Operation at 35℃, an initial biomass of 17.74 g·L^-1 and hydraulic retention time （HRT） of 6 h, the CSTR reactor presented a continuous hydrogen production ability of 5.9 L·d^-1 and the biogas was free of methane throughout the experiment. Dissolved fermehtation products were predominated by ethanol and acetate acid, with smaller quantities of propionic acid, butyric acid and valeric acid. It was found that GAC could make the immobilized system durable and stable in response to organic load impacting and low pH value. When the organic loading rate （OLR） ranged from 8 kgCOD/（m^3d） to 4 kgCOD/（m^3d）, stable ethanol-type fermentation was formed, and the ethanol and acetate concentrations account for 89% of the total liquid products.

牛瘤胃臌气病的诊治

牛瘤胃臌气病是兽医临床上常见的一种疾病,多发生于秋、冬两季,教科书上采用松节油、克辽林、稀盐酸、鱼石脂等多种制酵剂疗法和瘤胃穿刺放气等疗法,及时诊断和治疗能达到康复的目的。但是牛瘤胃臌气病防治知识普及不够,养牛户没有备好穿刺套管针和制酵剂,特别是急性牛瘤胃臌气易造成死亡和经济损失。笔者收集了洞口县近3年内几例牛瘤胃臌气病诊治病例,为养牛户提供参考。

Optimization of Sporulation Conditions of Biocontrol Bacteria B579 by Two-step Control Strategy

[Objective] For preparing the biopesticide of Bacillus subtilis B579 with high spore concentration,the sporulation conditions were optimized.[Method] Two-step fermentation control strategy was used,in which,the first phase（0-10 h）was to improve cell growth,and the second phase（10-30 h）was to promote spore formation.Four factors including initial glucose concentration,fermentation pH,temperature（in the second phase）and shaking speed（in the second phase）were optimized using the methods of single factor test and orthogonal experiment.[Result] The initial glucose concentration showed a significant effect on sporulation.The optimal conditions for the spore formation of B.subtilis B579 were as follows：initial glucose concentration 5 g/L,fermentation pH 7.0,the temperature for the first phase 37 ℃,and the shaking speed for the first phase 180 r/min,the temperature for the second phase 40 ℃,and the shaking speed for the second phase 200 r/min;in addition,the first phase was 10 h and the second phase of fermentation was conducted for 30 h.Under such conditions,the spore concentration and spore formation rate could reach 9.43×108 CFU/ml and 90.99%,respectively,which represented 6.70-fold and 2.43-fold increase compared with those before optimization.[Conclusion] The spores concentration of biocontrol agent was improved using two-step control strategy,which provided the basis for biopesticide production in large scale.

Study on the Substrate Inhibition and the Method of Disarming Inhibition in the Fermentation Process of Hyaluronic Acid

[Objective] The research aimed to search and obtain the fermentation method of hyaluronic acid with the high yield.[Method] In the production process of hyaluronic acid by the microbial fermentation method,the influence of substrate concentration on the fermentation was explored.[Result] The glucose had the biggest influence on the hyaluronic acid fermentation.The low concentration of glucose only could synthetize a little bacteria and hyaluronic acid,and the high concentration of glucose could inhibit the growth of bacteria and the formation of hyaluronic acid.Via the exploratory experiment,the fed-batch fermentation could disarm the substrate inhibition.The concrete method was adding 2% glucose before the start of fermentation,and adding 2% glucose at the 14th hour of fermentation,and adding 2% glucose again at the 22nd hour of fermentation.[Conclusion] In the microbial fermentation process,the fed-batch fermentation could disarm the substrate inhibition and obtain the hyaluronic acid with the larger relative molecular mass and the higher yield.

Process Analysis of Mobile Fermentation of Spent White Hypsizygus marmoreus Substrate with Self-made Mobile Fermentation Bag

The self-made mobile fermentation bag for spent white Hypsizygus marmoreus substrate was developed, and the relevant fermentation process was studied. The results showed that under the condition of single addition of Lactobacillus,nitrogen-free extract was degraded into lactic acid, leading to decreased pH value.On day 10, the fermentation effect reached the best with Lactobacillus abundance of 5.12×10~7/ml, lactic acid content of 0.48% and strong acid flavor. At this time, the fermentation material was moist without mildew and agglomeration, and was suitable for livestock and poultry. However, after 10 days, undesirable acids and mildew generated, a large amount of lactic acid bacteria died, and the fermentation material turned black and agglomerated, and became unsuitable for feeding livestock and poultry. Throughout the fermentation process, the pH value first decreased continuously until to 4.0, and then remained stable. During the fermentation of spent white H. marmoreus substrate, the nitrogen-free extract and crude fiber contents decreased, the crude protein content increased, while other indicators remained unchanged.

牛急性瘤胃臌气的症状与防治

牛急性瘤胃臌气病的症状为呼吸急促,心跳加快,脉搏增加,运动失调。可以用排气法治疗,为减少饲料在瘤胃内的发酵,可以在排气前或排气后灌服制酵剂,在发现牛有窒息危险时,可以采取手术法排气。

牛瘤胃臌气的治疗体会

作为兽医临床上常见的一种疾病,牛瘤胃臌气发病多在秋、冬两季.对于该病症的治疗通常选用的是包括消气灵以及稀盐酸等多种制酵剂疗法以及瘤位穿刺放气等方法,对于该病症的治疗应该注意及时的诊断和治疗.但是现在牛瘤胃臌气的防治知识普及状况并不高,相关的养殖人员一般都没有准备需要的制酵剂以及用来穿刺的穿刺套管针,这也是急性牛瘤胃臌气造成死亡和经济损失的重要原因.本文主要是对某地区牛瘤胃臌气治疗病例进行分析,为相关的养殖人员提供参考.

羊瘤胃臌气的临床症状与综合防治措施

羊瘤胃臌气是由于食入过多的容易发酵的饲料,在瘤胃内生成大量的气体,或者由于其他因素导致瘤胃内无法正常排出气体而在瘤胃和网胃内大量积聚,压迫膈与胸腔器,造成呼吸和血液循环出现障碍,甚至引起窒息而发生死亡,尤其是采食大量青草或者露水草最容易发病。

牛瘤胃臌气病的发病与防治措施

牛瘤胃臌气病牛患上的一种常见疾病,在传统的养殖户的应对措施中,多是通过采用松节油、克辽林、稀盐酸、鱼石脂等多种制酵剂疗法和瘤胃穿刺放气等疗法。但是由于牛瘤胃臌气病的预防知识在乡村的普及力度不够以及该操作方法有些复杂导致养殖者难以实施控制防治牛瘤胃臌气病的发生。本文以四川地区的牛瘤胃臌气病为例,分析该病的发病原因以及探讨该病况的防治措施。

家畜肠臌气的综合诊治

肠臌气是由于采食大量易发酵饲料,肠内产气过盛,而排气不畅,致使肠管过度臌胀的腹痛病。中兽医称为胀肚,临床上以经过短急、腹围急剧膨大,剧烈而持续的腹痛为特征。分原发性和继发性肠臌气两种,后者较前者多见,文中探讨相关的综合防治措施。

Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

To investigate the characteristics and metabolic mechanism of short-cut denitrifying phospho- rus-removing bacteria （SDPB） that are capable of enhanced biological phosphorus removal （EBPR） using nitrite as an electron acceptor, an aerobic/anoxic sequencing batch reactor was operated under three phases. An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological, physiological, biochemical properties and 16S rDNA gene sequence analysis. Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand （COD）, phosphate, nitrite, poly-fl-hydroxybutyrate （PHB）, and glycogen. The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans. As a kind of non-fermentative bacteria, the energy of strain YC was mainly generated from phosphorus release （96.2%） under anaerobic conditions with 0.32 mg P per mg synthesized PHB. Under anoxic conditions, strain YC accumulated 0.45 mg P per mg degraded PHB, which produced most of energy for phosphate accumulation （91.3%） and a little for glycogen synthesis （8.7%）. This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms （PAOs）. It is also found that PHB, a kind of intracellular polymer, plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification. Therefore, monitoring AP/APHB and ANO2 -N/APHB is more necessary than monitoring AP/ACOD, ANO2 -N/ACOD, or AP / ANO2 -N.

Multiobjective optimization and multivariable control of the beer fermentation process with the use of evolutionary algorithms

This paper describes empirical research on the model, optimization and supervisory control of beer fermentation.Conditions in the laboratory were made as similar as possible to brewery industry conditions. Since mathematical models that consider realistic industrial conditions were not available, a new mathematical model design involving industrial conditions was first developed. Batch fermentations are multiobjective dynamic processes that must be guided along optimal paths to obtain good results.The paper describes a direct way to apply a Pareto set approach with multiobjective evolutionary algorithms (MOEAs).Successful finding of optimal ways to drive these processes were reported.Once obtained, the mathematical fermentation model was used to optimize the fermentation process by using an intelligent control based on certain rules.

Hydrogen producting characteristics by a novel strain of bacteria-ethanoligenens sp. B49

The objective of this work is to investigate the fermentation capacity and metabolic characteristics of a novel strain of bacteria B49 isolated from anaerobic activated sludge. The examination was conducted in batch culture at 35 ℃. The results showed that the carbon flow gave priority to the production of ethanol, and yield of ethanol is always greater than that of acetic acid. The hydrogen and ethanol occurred simultaneously. The exponential phase of the B49's cell growth was from 12 to 22 h. Evolution of hydrogen appeared to start after the exponential phase of cell growth and reach maximum production at the early stationary phase. The rate of hydrogen production reached a maximum of 16.8 mL/h, and the percentage of hydrogen gas in the headspace of serum bottle obtained a maximum of 41 % at 22 h. The B49 was able to grow using molasses as substrate for cell growth. When the molasses was used as substrate, maximum yield of hydrogen was obtained 2460 mL/L culture at 2 % (V/V) of molasses. The hydrogen yield was increased to 3060 mL/L culture after addition of 0.5 g/L of yeast extract in the molasses medium and the yield of hydrogen was increased by 24.4%.

An Optimal Control Strategy Combining SVM with RGA for Improving Fermentation Titer

An optimal control strategy is proposed to improve the fermentation titer,which combines the support vector machine(SVM)with real code genetic algorithm(RGA).A prediction model is established with SVM for penicillin fermentation processes,and it is used in RGA for fitting function.A control pattern is proposed to overcome the coupling problem of fermentation parameters,which describes the overall production condition.Experimental results show that the optimal control strategy improves the penicillin titer of the fermentation process by 22.88%,compared with the routine operation.

Ant colony system algorithm for the optimization of beer fermentation control

Beer fermentation is a dynamic process that must be guided along a temperature profile to obtain the desired results. Ant colony system algorithm was applied to optimize the kinetic model of this process. During a fixed period of fermentation time, a series of different temperature profiles of the mixture were constructed. An optimal one was chosen at last. Optimal temperature profile maximized the final ethanol production and minimized the byproducts concentration and spoilage risk. The satisfactory results obtained did not require much computation effort.

Viral infections and cell cycle G2/M regulation

Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast (Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15 (Tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. These Cdc2 regulators are the downstream targets of two well- characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins, which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest. Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small T antigen, polyomavirus T antigen, HTLV Tax and adenovirus E4orf4. Thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

Dietary and socio-economic factors in relation to Helicobacter pylori re-infection

AIM:To examine if dietary and socio-economic factors contribute to Helicobacter pylori(H pylori)re-infection. METHODS:The population of patients consisted of subjects in whom H pylori infection had been successfully treated in the past.Patients were divided into two groups:Ⅰ-examined group(111 persons with H pylori re-infection)andⅡ-control group(175 persons who had not been re-infected).The respondents were interviewed retrospectively on their dietary habits and socio-economic factors. RESULTS:A statistically significant lower frequency of fermented dairy products(P<0.0001),vegetables (P=0.02),and fruit(P=0.008)consumption was noted among patients with H pylori re-infection as compared to those who had not been re-infected. CONCLUSION:High dietary intake of probiotic bacteria,mainly Lactobacillus,and antioxidants,mainly vitamin C(contained in fruit and vegetables),might decrease the risk of H pylori re-infection.

On-line Estimation in Fed-batch Fermentation Process Using State Space Model and Unscented Kalman Filter

On-line estimation of unmeasurable biological variables is important in fermentation processes,directly influencing the optimal control performance of the fermentation system as well as the quality and yield of the targeted product.In this study,a novel strategy for state estimation of fed-batch fermentation process is proposed.By combining a simple and reliable mechanistic dynamic model with the sample-based regressive measurement model,a state space model is developed.An improved algorithm,swarm energy conservation particle swarm optimization(SECPSO) ,is presented for the parameter identification in the mechanistic model,and the support vector machines(SVM) method is adopted to establish the nonlinear measurement model.The unscented Kalman filter(UKF) is designed for the state space model to reduce the disturbances of the noises in the fermentation process.The proposed on-line estimation method is demonstrated by the simulation experiments of a penicillin fed-batch fermentation process.