Fermentative production medium composition

Filter aids are widely used in die fermentation industry to improve the efficiency of filtration. It is a pre-coated filter medium to prevent blockage or blinding of the filter by solids, which would otherwise wedge diemselves into the pores of the cloth. Filter aid can be added to the fermentation broth to increase the porosity of the cake as it formed. This is only recommended when fermentation product is extracellular. Filter aid adds to the cost of filtration. The minimum quantity needed to achieve the desired result must be established experimentally. Fermentation broths can be pretreated to improve filtration characteristics. Heating to denature proteins enhances the filterability of mycelial broths such as in penicillin production. Alternatively, electrolytes may be added to promote coagulation of colloids into larger, denser particles, which are easier to filter. The filtration process is affected by the viscosity and composition of the broth, and the cell cake.5... 

Initial scale-up of microbial biotransformation is conveniently run with multiple flasks without extensive reaction optimization. A typical flask fermentation is performed at 28 °C, 250 rpm with 100 mL culture in a 500 mL Erlenmeyer flask, although other settings will work fine too. Three parameters need to be investigated before scale-up the time for adding the substrate, the optimal substrate concentration and the time course of product formation. Optimization of other factors, such as medium composition and pH, growing cells versus resting cells [74], is helpful, if the timeline allows and if there is a sufficient amount of the substrate to support the screening. 

The medium composition used in the fed-batch process was optimized, resulting in cell densities near 100 g l-1. By using an exponential feed rate resulting in a growth rate of 0.05 h-1, a maximum biomass concentration of 112 g 1 1 was attained, with a biomass productivity of 1.8 g 1 1 h. The poly(3HAMCL) productivity however was low, 0.34 g 1 1 h, caused by a steady decrease of the poly(3HAMCL) content during the last part of the fermentation [51]. When this optimized medium composition was used in the continuous culture system described above, a maximum biomass concentration of 18 g 1 1 was reached. The PHA content however remained low at approximately 10% [51]. It is still unclear what causes these low PHA contents. 

The composition of the products was monitored by HPLC (Sugar Analyzer, Waters Associates HPX-87C column, BioRad Corp. with deionized water, 40 ppm in calcium acetate as mobile phase). During fermentation, the sucrose levels dropped and fructan started to appear in 2 days thereafter, sucrose level gradually decreased as fructan increased. Glucose was the major by-product. A small amount of fructose and other unidentified fermentation products smaller in molecular weight were also observed. The pH of the growth medium was controlled, and fell from... 

Figure 6.3 Effect of fermentation medium composition on the rate of ethanol production from glucose using extruded yeast pellets. Reproduced from Hayes (1998) with permission.

Despite the excellent properties of honey, mead production faces several problems, namely, delays and pouts fermentations, lack of product uniformity, and production of yeast off-flavors. Many factors might be related with these problems, such as honey variety, temperature, medium composition (vitamin and nitrogen content), fermentative yeast, and pH. Due to all these factors, mead production has decreased over the years. To overcome this situation, more research is needed to optimize the production of this beverage. 

The operating conditions for solid-state fermentation for cellulase production are dependent on the strain to be used, the reactor type and the medium composition, but the basic operating procedure remains the same as shown in Fig. 2. The final product can be obtained as crude solid cellulase, liquid cellulase or powder cellulase according to the application. Figure 3 shows a process flowsheet for cellulase production [25]. In the process, wheat bran is used as substrate. Seeds are prepared in a stirred-tank fermentor and then sprayed into the medium by a spray distributor. The fermentation is performed in a shallow-tray fermentor. The temperature and humidity in the fermentor are automatically regulated. After fermentation, cellulase is recovered by water extraction and purified by salt precipitation and ion exchange. The final product is concentrat-... 

Parameters to describe a solid-state fermentation process for cellulase production include physical properties such as temperature, pH, humidity and water activity, particle size, pile and real densities, pore size and porosity, etc. chemical components such as medium composition, gas-phase composition, amount and properties of microorganisms, activities of cellulases, etc. and kinetic para-... 

It is generally agreed among the practitioners of whole beer processing that product removal in the presence of cells is more difficult to attain, and requires that all physico-chemical parameters of the operation such as fermentation medium composition to be standardized. The purpose of this paper is to describe a new approach to achieve whole broth processing using immobilized solid phase adsorbents. 

Preliminary experiments indicated that the activity of bacitracin production by immobilized whole cells was remarkably reduced at the second reaction when a fermentation medium was used. Furthermore, the growth of leaked bacteria was observed when a fermentation medium (starch-bouillon) was employed for bacitracin production. Therefore, the effect of medium composition on bacitracin productivity was examined. As shown in Table III, bacitracin productivity in a medium... 

Yeast flocculation, an essential phenomenon in beer fermentation, is influenced by the medium composition, especially by the glucose concentration, and is delayed by the mixing effect of CO2 production. The time variation of the suspended yeast concentration is thus taken as the difference between the growth and flocculation rate as ... 

Figure L Effect of medium composition and initial pH on xylanase production by AspergUlus oryzae strains in SSF on eucalyptus pidp (T, 30°C iniHal moisture content, 83% , initial pH, 8.3, fermentation time, 4 d). Medium / (g/l) NH4NO3, 5 Corn steep liquor (50% dry weight), 2 KH2PO4, 5 NaCi, 1 M 04, / trace element solution I, fl I ml/l. Medium II (g/l) (NH4)2HP04f 4 Corn steep liquor (50% dry weight), 2 urea, I KH2PO4, 3 NaCl, 1 M 04,1 trace dement solution I and II, I ml/l...

Industrial fermentations are used for manufacturing of bioproducts . They predominantly use glucose as a feedstock for the production of proteins, enzymes and chemicals. These fermentations can be batch, fed-batch, or continuous, and operate under controlled-substrate feeding and conditions that form minimal byproducts. Substrate-controlled feeding, pH, dissolved oxygen, and medium composition are critical operating conditions that must be controlled during fermentation in order to optimize fermentation time, yield and efficiency. Currently used methods and feedstocks, however, have drawbacks that reduce the efficiency of the fermentation processes. 

AH fermentation processes mentioned in Table 5.1 have been optimized concerning their medium composition and substrates for many years and at the moment no better substrates will be available according to microbial growth, production yields, and raw material prices. 

Microbial chitin and chitosan productions are affected by different factors such as medium composition, temperature, pH, aeration, agitation, size and age of the producing microbial cells, and growth time. Each factor can have various effects on chitin/chitosan production depending on fermentation technique and microorganism under examination. 

A characteristic of A. mediierranei fermentations is the very high oxygen requirement in a definite period of the growth—production cycle. The time at which this occurs varies with the strain and the medium composition, but it always coincides with the phase in which glucose is rapidly metabolized. If this demand is not met by an adequate oxygen supply through aeration, very low final yields of rifamycin B are obtained. 

The development of a bioconversion/fermentation process consists of several stages, namely, bench, pilot, and plant scale. The outcome of the bench scale establishes key conditions for the upcoming stages, and the relevant aspects of the process (viz., medium composition and concentrations of different species involved, temperature and pH of operation, conditions that optimize productivity) are expected to be reproduced as closely as possible when larger vessels are used. In order to achieve this, several aspects have to be considered. Unfortunately, it has been shown that there is not a single criterion for scale-up, yet a set of guidelines has to be considered. 

Microbial EPS production is achieved by fermentation that is a very versatile process technology for producing value-added products. Since fermentation conditions such as medium composition, pH, temperature, aeration, as well as mode of operation are known to have a h h impact upon the viabihty and economics of the bioprocess, their optimization is compulsory in designing a profitable bioprocess. Moreover, structural features and associated physicochemical and rheological properties of the EPS are largely... 

Harazim, R, Malinka, Z. and Bfemek, J. (1986) Influence of inoculation mediums composition with different carbon source on fermentative production of lysergic acid alpha-hydroxyethylamide. Abstract Book, 17th Congr. Czecboslov. Microbiol. Soc., Ceske Budejovice, Czechoslovakia, September23-25,1986, p. A-16 (In Czech). 

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