Penicillin production

A typical fermentation medium for penicillin production contains lactose, com steep Hquot, and calcium carbonate (3,153,154). In most industrial processes the carbohydrate source, glucose, beet molasses, or lactose, is continuously added to the fermentation. The rate of glucose addition must be carefully monitored, by pH or rate of oxygen depletion, because the synthesis of penicillin is markedly reduced in the presence of excess glucose. 

Fine chemicals There are many applications of the austenitic steels in the manufacture and storage of fine chemicals and pharmaceutical products. These include storage tanks, pipelines, valves, stills, steam-jacketed pans, mixing vessels, filters and tableting machinery. Considerable use has been made of these steels in penicillin production. 

Figure 6.4 Stylised representation of changing parameters and penicillin production in cultures of Penldlllum notatum, grown as a surface culture on Czapek-Dox medium (adapted from Hockenhull DJ-D "Production of Antibiotics by Fermentation in Essays in Applied Microbiology edited by Norris J R Richmond M H 1981. John Wiley Sons Ltd Chichester).

So far we have shown how, by manipulating the formulation of media, improvements in product yield and product diversification were achieved in the early years of penicillin production. We have deliberately selected the high points of these development activities. We will now turn our attention to another aspect of the development of penicillin production the switch from surface to deep culture. 

Figure 6.6 Production of penicillin using pre-set feed patterns. Note that increase in biomass occurs over the first short phase, while the penicillin production phase is maintained for a much longer period.

You may for example have suggested that the supply of other nutrients, such as ammonia and O2, may be adjusted to respond to the different needs of growth and penicillin production. You may also have suggested that precursors of specific penicillins, such as P-phenylacetic add, may be added after the growth phase is complete. You may have also considered altering physical parameters such as pH and temperature. 

Now that we have provided you with an overview of the history of penicillin production, we will examine some more details of the biotransformation of -lactams. We will briefly outline the normal biosynthesis pathways that lead to their production and then consider how these products may be diversified in vitro to give a wider range of valuable compounds. We begin by briefly explaining how the fi-lactam antibiotics are effective as therapeutic agents. 

In this chapter, by using the examples of -lactams we have briefly examined how microbial cultures may be used to produce sufficient antibiotics to meet market demands. We have also explained how enzymes (or cells) may be used to biotransform, and thereby diversify, antibiotics. By outlining the history of penicillin production, we explained how analysis and manipulation of culture regimes may be used to enhance the yields of antibiotics (and other secondary products). These studies led to die concept of directed biosynthesis by precursor feeding. 

Example 1.1 Effect of Carbon Source in Penicillin Production... 

The carbon source affects oxygen demand. In penicillin production, oxygen demand for glucose is 4.9 mol 1 1 h-1. The lactose concentration is 6.7 mol 1 1 h 1, sucrose is 13.4 mol l-1 h. The yield of oxygen per mole of carbon source for CH4 is YQjC = 1.34, T0j/C for Paraffins = 1, and Y(> /c for hydrocarbon (CH20)n = 0.4. The mass transfer coefficient k,a is for gas-liquid reactions, and the film thickness where the mass transfer takes place is 8... 

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... 

Also, moles of glucose needed in penicillin production are based on a stoichiometric relation ... 

The War ended on the 15th of August in 1945. H. Umezawa considered the defeat to be a natural result. In that September, he was instructed by the last director of the Military Medical School to explain the Japanese state of penicillin production to the General Headquarters (GHQ)... 

The growth phase passes rapidly into the antibiotic-production phase. The optimum pH and temperature for growth are not those for penicillin production and there may be changes in the control of these parameters. The only other event that marks the onset of the production phase is the addition ofphenylacetic acid (PAA) by continuous feed. 

There comes a time when sequential improvements in penicillin productivity obtained by standard strain improvement techniques (physical and chemical mutagenesis in conjunction with a variety of selection techniques that apply pressure for high-yielding variants) become subject to rate-limiting returns. At first, it is easy to double the titre with each campaign later in the genealogy even a 5% improvement would be regarded as excellent. 

The 1980 s and the early 1990 s have seen the blossoming development of the biotechnology field. Three-phase fluidized bed bioreactors have become an essential element in the commercialization of processes to yield products and treat wastewater via biological mechanisms. Fluidized bed bioreactors have been applied in the areas of wastewater treatment, discussed previously, fermentation, and cell culture. The large scale application of three-phase fluidized bed or slurry bubble column fermen-tors are represented by ethanol production in a 10,000 liter fermentor (Samejima et al., 1984), penicillin production in a 200 liter fermentor (Endo et al., 1986), and the production of monoclonal antibodies in a 1,000 liter slurry bubble column bioreactor (Birch et al., 1985). Fan (1989) provides a complete review of biological applications of three-phase fluidized beds up to 1989. Part II of this chapter covers the recent developments in three-phase fluidized bed bioreactor technology. 

Nagamune, T., Endo, I., Kato, N., Nishimura, M., and Kobayashi, T., The Effect of Cultivation Conditions on the Penicillin Production Using a Urethane Foam-Supported Penicillium chrysogenum, Bioproc. Eng., 3 173 (1988)... 

Figure 12.4 illustrates some modes of operation of semicontinuous reactors. In Figure 12.4(a), depicting a gas-liquid reaction of the type A(g) + B(f) - products, reactant A is dispersed (bubbled) continuously through a batch of reactant B an important example is an aerobic fermentation in which air (or 02) is supplied continuously to a liquid substrate (e.g., a batch of culture, as in penicillin production). In Figure 12.4(b),... 

HPLC-controlled analysis of a microbiological process during Penicillin Production Chromatographic conditions are as follows ... 

---