Tanks sterilization

Bacterium seeds, water, and methanol are fed into an inoculation tank. Sterilized air and nutrients are then injected into the fermenter along with an inoculum of cultivated bacteria. Ammonia is added as a nitrogen source and for pH control Continuous fermentation produces a steady stream of bacteria, which are sent into a flocculation tank after filtration and centrifu l separation. The concentrated effluent from the flocculation tank is further dewatered by a series of decanter centrifuges. SCP destined for human consumption must under an additional step to remove the nucleic acids contained in the cells by one of the following techniques [4] (1) acid hydrolysis, (2) cell disruption, (3) chemical extraction, (4) alkaline hydrolysis, or (5) enzymatic treatment. Finalfy, the concentrated product stream is dried and processed into granules, pellets, or powder and then packed for sale. The overall yield is 1 ton protein for every 1.8 ton methanol consumed in the process. 

Sterile Filtration of Gases. Primary appHcations for sterile gas filtration are the sterilization of fermentor inlet air, fermentor vent gas, vents on water for injection tanks, and vacuum break filters during lyophilization. Operational and process considerations apply. Typically, the membrane in gas... 

Fig. 5. Fermentative production of amino acids (140). A, pure culture B, inoculation C, boiler D, air compressor E, air filter F, seed tank G, ammonia water for pH control H, fermenter I, sterilizer , culture media K, preparation tank L, centrifugal separator M, ion-exchange column N, crystallizing...

Pasteurization does not mean sterilization of the beer, ie, killing all microorganisms, but rather a reduction and inactivation of the microorganisms. The result of the heat treatment depends not only on time and temperature, but also on the number of microorganisms present. It is important that tanks. 

Many processes use sealed tanks and reactor vessels. For example, in a milk processing plant or a pharmaceutieal plant, it s necessary to present outside air from contaminating the sterile produet. In a beer brewery, you can t let the gas and carbonization escape from the proce.ss. In a closed un-pressurized vessel, the Ha is equal to the Hvp. And because the Ha adds energy and the Hvp subtracts energy, they cancel themselves. The formula is simpler ... 

Generally, the fermentation proeess involves the addition of a speeifie eulture of mieroorganisms to a sterilized liquid substrate or broth in a tank (submerged fermentation), addition of air if aerobie, in a well-designed gas-liquid eontaetor. The fermentation proeess is then earried out to grow mieroorganisms and to produee the required ehemieals. Table 11-1 lists examples of the proeesses used by fermentation. 

The medium was contained in a 100 liter stainless steel baffled fermenter, agitated by a TA inch vaned disc impeller at 140 rpm. Sterile air was supplied at 75 liters per minute and the tank incubated for 72 hours at 26°C. 

The broth is placed in an iron tank of 350 gallon capacity and is sterilized by heating it under pressure at a temperature of about 120°C for 30 minutes. The sterilized broth is cooled and inoculated aseptically with spores oi Streptomyces erythreus, NRRL 2338. 

Tank fermentation of Micromonospora inyoensis — Germination stage 1 Under aseptic conditions, add a lyophilized culture (or cells obtained from a slant culture) of M. inyoensis to a 300 ml shake flask containing 100 ml of the following sterile medium ... 

The above sterilized medium was inoculated with 11 liters of seed inoculum having a bacterial count of approximately 20 billion per cc. The tank was fermented at 37°C without pH adjustment, aeration, or other modification for 14 hours at the end of which time 320 cc of 50% dextrose was added. After this the pH was adjusted to 7.0 at 15 minute intervals with 5.0 N sodium hydroxide. The volume of sodium hydroxide required for neutralization was noted and 115% of this volume of 50% dextrose solution added after each pH adjustment. At the end of about 8 hours the bacterial count had ceased to increase and the fermentation was terminated. At this time the fermentation medium contained approximately 1,000 units of streptokinase per cc. 

A small fermentation tank (5,000 parts by volume capacity) was charged with 3,000 parts by volume of a culture medium (pH 6.0) comprising 3% glucose, 1 % polypepton, 0.5% yeast extract and 0.5% malt extract. The medium was sterilized by heating in a conventional manner and cooled. This medium was inoculated with 150 parts by volume of a pre[Pg.1565]

Dilution rate is defined as the number of tank volume pass through per unit time, D = F/V. The residence time is defined as the tune required for one unit volume of reactor to be replaced by the flow rate, t = VIv. When feed is sterile, there is no cell entering the bioreactor, which means x0 = 0, the rate may be simplified and reduced to ... 

All of the above processes are operated as batch fermentations, in which a volume of sterile medium in a vessel is inoculated. The broth is fermented for a defined period. The tank is then emptied and the products are separated to obtain the antibiotic. The vessel is then recharged for batch operation with medium and the sequence repeated, as often as required. Continuous fermentation is not common practice in the antibiotics industry. The antibiotic concentration will rarely exceed 20gT 1 and may be as low as 0.5g-l 1. 

NOTE Where RW quality is poor, a booster unit is generally required on the front of the multifunctional tank, so that the concept of a single tank is lost. Additionally, where iron- and sulfate-reducing bacteria may be present, periodic sterilization of the bed using chlorine injection becomes necessary. 

However, it should be noted that there is a small percentage of the total time in which productivity rate is near its maximum. It is sometimes possible to maintain very high rates of products for a long time with continuous fermentation. Although it can get much more productivity from the fermentor, enhancement over batch fermentation in terms of the total volume of fermentor is not high because equipment needs to be sterilized to support the continuous tank. 

In the first example, procaine penicillin, an aqueous vehicle containing the soluble components (such as lecithin, sodium citrate, povidone, and polyoxyethylene sorbitan monooleate) is filtered through a 0.22 pm membrane filter, heat sterilized, and transferred into a presterilized mixing-filling tank. The sterile antibiotic powder, which has previously been produced by freeze-drying, sterile crystallization, or spray-drying, is aseptically added to the sterile solution while mixing. After all tests have been completed on the bulk formulation, it is aseptically filled. 

The design of equipment for use in controlled environment areas follows similar principles, whether for general injectable manufacturing or for the manufacturer of sterile ophthalmic pharmaceuticals. All tanks, valves, pumps, and piping must be of the best available grade of corrosion-resistant stainless steel. In general, stainless steel type 304 or 316 is preferable. 

The term chemostat refers to a tank fermentation which is operated continuously. This bioreactor mode of operation normally involves sterile feed (Xo=0), constant volume and steady state conditions, meaning that dV/dt=0, d(VSd/ dt=0, d VX1)/dt=0. 

---