Scale-up thermostable α-amylase production in lab-scale fermenter using rice husk as an elicitor by Bacillus licheniformis-AZ2 isolated from Qinarje Hot Spring (Ardebil Prov. of Iran)

Background and purpose: Amylases are commercially important enzymes with various biotechnological, clinical and medical applications. This study aimed at scaling up α-amylase production elicited by rice husk in stirred-fermenter using Bacillus lichneniformis-AZ2 isolated from Qinarje Hot Spring. Materials and methods: Effect of temperature, aeration rate and agitation speed on bacterial growth and ɑ-amylase production were investigated under batch fermentation process in a 3-Lit stirred-fermenter. OFAT method was followed to select optimum level of each parameter. Other factors were set upon the results of previous experiments carried out in shake-flask scale. Results: Maximum α-amylase production of 17.66 ± 0.87 U/mL (2.1 folds more than shake-flask cultures) was achieved in stirred-fermenter with optimized agitation speed of 100 rpm and 1 vvm aeration rate at 37ºC after 60 h of incubation. This time was shorter than the corresponding fermentation time obtained from shake-flask experiments by half. A comparison of kinetic parameters of fermentation in stirred-fermenter and shake-flask cultures revealed that B. licheniformis-AZ2 was more active to synthesize ɑ-amylase in fermenter. In shaken cultures Qx, Qp, Yp/x, µmax, qp and td, were 0.27 (g/L/h), 228.6 (U/L/h), 13.64 (U/g), 0.055 (h-1), 0.76 (U/g/h) and 12.48 h, whereas in stirred-fermenter the above values were 0.40 (g/L/h), 723.1 (U/L/h), 45.17 (U/g), 0.120 (h-1), 5.42 (U/g/h) and 5.78 h, respectively. Conclusions: SmF in stirred-fermenter is a potential strategy for ɑ-amylase production. Although for commercialization further studies are needed in pilot-scale. Rice husk as a low-cost agro-waste is preferable to use as the carbon and energy sources, which provides a great ɑ-amylase elicitation.</p

Design of a Batch Stirred Fermenter for Ethanol Production

AbstractThis paper addresses the batch stirred bioreactor design for ethanol production with yeasts Saccharomyces cerevisiae under anaerobic conditions carried out to improve the performance of the fermentation process. A large, appropriate – sized fermenter is supposed 70 m3. The operating volume is 52,5 m3. Batch fermentation was perform with 200g/l glucose concentration. Fermentation time, is 11,4hours with ethanol stripping 69,1g.l-1 and 12hours 75,9g.l-1 without stripping. Computing is stopped when glucose alteration obtain 97 percent. The kinetic constants (Ks, Kp, μmax) of batch fermentation were 2,0kg.m-3, 97,9kg.m-3, 0,476 h-1 respectively. Output per a batch is 3 623kg and a single fermenter can produce 514 batches per year. From it follows that the year vintage is close to the actual 1 862 222kg. Therefore, the number of 70 m3 fermenters required 4 bioreactor. Whole heat exchange and heat surface area estimated 338437J/s and 40 m2 respectively. The maximum yield of biomass on substrate (YX/S) and the maximum yield of product on substrate (YP/S) in batch fermentation were 82% and 35,5% respectively. The present research has shown that high sugar concentration (200g/l) in the batch stirred bioreactor was successfully converted to ethanol. The achieved results in batch stirred bioreactor with high substrate concentration are promising for scale up operation. The proposed model can be used to design a larger scale batch stirred bioreactor for production of high ethanol concentration

CFD stimulation of gluconic acid production in a stirred gas-liquid fermenter

Designing large-scale stirred bioreactors with performance closely matching the one achieved in lab-scale fermenters presents continuous challenge. In this contribution, dynamic modelling of the aerobic biocatalytic conversion process in viscous batch stirred tank reactor is developed. Its operation is illustrated by simulation of the interaction of fluid flow, mass transfer and reaction relevant to gluconic acid production by a strictly aerophilic Aspergiluc niger based on a “twofluid” model. As a result of this simulation, the velocity fields, the local substrate, dissolved oxygen, product and biomass concentration profiles were obtained. Constant bubble size and global gas-liquid mass transfer were assumed. The algorithm employed could be used for fast evaluation procedures regarding predictions and feedback control of aerobic bioreactor performance

Diseño y optimización de un sistema piloto de fermentación en batch para la producción de bioetanol

An "in house" fermentation system has been designed on a laboratory scale, which would be used in a batch fermentation process of the Zymomonas mobilis to obtain bioethanol from the biomass degradation of the Eichhornia crassipes. This model is proposed starting from simple tools and laboratory equipment that at a small scale allow simulating alcoholic fermentation by controlling the aeration, the pH, the temperature, the amount of glucose, and the concentration of the product so that the model has been used for the future optimization of the same, and reliable bioethanol obtaining as well as production control.Se ha diseñado un sistema de fermentación “in house” a escala de laboratorio, el cual será utilizado en un proceso de fermentación batch de la bacteria Zymomonas mobilis, para obtener bioetanol a partir de la de degradación de biomasa de la Eichhornia crassipes. Este modelo se propone partiendo de herramientas y equipos de laboratorio sencillos que a baja escala permiten simular una fermentación alcohólica controlando la aireación, pH, temperatura, cantidad de glucosa y la concentración de producto, de tal manera que el modelo optimizado sea usado para la futura fermentación y obtención confiable de bioetanol, así como el control de la producción

PROCESS OPTIMIZATION FOR AMYLOGLUCOSIDASE BY A MUTANT STRAIN OF ASPERGILLUS NIGER IN STIRRED FERMENTER

Abstract The present study was designed to optimize the process parameters for the production of amyloglucosidase bya mutant strain of Aspergillus niger in stirred fermenter by. For this purpose, various cultural conditions like rate of fermentation, process pH, rate of agitation and size of inoculum was investigated. The maximum production (25.15 U/mL/min) of amyloglucosidase was achieved at the agitation speed of 200rpm. The production of amyloglucosidase was found to be maximum (25.08 U/mL/min) at pH 5 of the medium. The optimum productivity (25.15 U/mL/min) of the enzyme was achieved with 4% inoculum after 48 h of incubation. The process temperature was optimized at 30 o C throughout the study

Studies supporting the use of mechanical mixing in large scale beer fermentations

Brewing fermentations have traditionally been undertaken without the use of mechanical agitation, with mixing being provided only by the fluid motion induced by the CO2 evolved during the batch process. This approach has largely been maintained because of the belief in industry that rotating agitators would damage the yeast. Recent studies have questioned this view. At the bench scale, brewer’s yeast is very robust and withstands intense mechanical agitation under aerobic conditions without observable damage as measured by flow cytometry and other parameters. Much less intense mechanical agitation also decreases batch fermentation time for anaerobic beer production by about 25% compared to mixing by CO2 evolution alone with a small change in the concentration of the different flavour compounds. These changes probably arise for two reasons. Firstly, the agitation increases the relative velocity and the area of contact between the cells and the wort, thereby enhancing the rate of mass transfer to and from the cells. Secondly, the agitation eliminates spatial variations in both yeast concentration and temperature, thus ensuring that the cells are maintained close to the optimum temperature profile during the whole of the fermentation time. These bench scale studies have recently been supported by results at the commercial scale from mixing by an impeller or by a rotary jet head, giving more consistent production without changes in final flavour. It is suggested that this reluctance of the brewing industry to use (adequate) mechanical agitation is another example where the myth of shear damage has had a detrimental effect on the optimal operation of commercial bioprocessing

混合促進に着目した麹菌Aspergillus oryzaeを用いたα－アミラーゼ生産のプロセス強化に関する研究

博士（工学）神戸大

Lactic acid production from lime-treated wheat straw by Bacillus coagulans: neutralization of acid by fed-batch addition of alkaline substrate

Conventional processes for lignocellulose-to-organic acid conversion requires pretreatment, enzymatic hydrolysis, and microbial fermentation. In this study, lime-treated wheat straw was hydrolyzed and fermented simultaneously to lactic acid by an enzyme preparation and Bacillus coagulans DSM 2314. Decrease in pH because of lactic acid formation was partially adjusted by automatic addition of the alkaline substrate. After 55 h of incubation, the polymeric glucan, xylan, and arabinan present in the lime-treated straw were hydrolyzed for 55%, 75%, and 80%, respectively. Lactic acid (40.7 g/l) indicated a fermentation efficiency of 81% and a chiral l(+)-lactic acid purity of 97.2%. In total, 711 g lactic acid was produced out of 2,706 g lime-treated straw, representing 43% of the overall theoretical maximum yield. Approximately half of the lactic acid produced was neutralized by fed-batch feeding of lime-treated straw, whereas the remaining half was neutralized during the batch phase with a Ca(OH)2 suspension. Of the lime added during the pretreatment of straw, 61% was used for the neutralization of lactic acid. This is the first demonstration of a process having a combined alkaline pretreatment of lignocellulosic biomass and pH control in fermentation resulting in a significant saving of lime consumption and avoiding the necessity to recycle lime

Effect of hydromechanical forces on the production of filamentous haemagglutinin and pertussis toxin of Bordetella pertussis

The production of Bordetella pertussis extracytoplasmic filamentous haemagglutinin (FHA) and pertussis toxin (PT) in a bioreactor under stirring conditions was studied in order to investigate the effect of hydromechanical forces on yields of both antigens. It was shown that FHA loses its haemagglutinin activity when the power transmitted by the agitator and the aerator per unit volume increases, whereas PT production is not affected. The loss of FHA activity can be explained by the action of shear forces on the filamentous structure of this antigen.Centro de Investigación y Desarrollo en Fermentaciones Industriale