Investigations of the production of cephalosporin C by Acremonium chrysogenum.

A review is given on the morphology of Acremonium chrysogenum and the biosynthesis of cephalosporin C based on the published references. Investigations are presented on the comparison of cultivation media carried out by means of shake flask cultures. The process performance of a standard cultivation in well controlled bioreactor is presented and compared with other cultivations, which were executed with the same strain and bioreactor, but with various carbon-, nitrogen- and sulphur-sources keeping the concentrations of the key components at definite levels. Also the influence of dilution and enrichment of the medium on the process performance is explored. Mathematical models for the growth of Acremonium chrysogenum and production of cephalosporin C are reviewed and their application for control of industrial processes with complex cultivation media are discussed.

Industrial enzymatic production of cephalosporin-based beta-lactams.

Cephalosporins are chemically closely related to penicillins both work by inhibiting the cell wall synthesis of bacteria. The first generation cephalosporins entered the market in 1964. Second and third generation cephalosporins were subsequently developed that were more powerful than the original products. Fourth generation cephalosporins are now reaching the market. Each newer generation of cephalosporins has greater Gram-negative antimicrobial properties than the preceding generation. Conversely, the 'older' generations of cephalosporins have greater Gram-positive (Staphylococcus and Streptococcus) coverage than the 'newer' generations. Frequency of dosing decreases and palatability generally improve with increasing generations. The advent of fourth generation cephalosporins with the launch of cefepime extended the spectrum against Gram-positive organisms without a significant loss of activity towards Gram-negative bacteria. Its greater stability to beta-lactamases increases its efficacy against drug-resistant bacteria. In this review we present the current situation of this mature market. In addition, we present the current state of the technologies employed for the production of cephalosporins, focusing on the new and environmentally safer 'green' routes to the products. Starting with the fermentation and purification of CPC, enzymatic conversion in conjunction with aqueous chemistry will lead to some key intermediates such as 7-ACA, TDA and TTA, which then can be converted into the active pharmaceutical ingredient (API), again applying biocatalytic technologies and aqueous chemistry. Examples for the costing of selected products are provided as well.

Industrial production of beta-lactam antibiotics.

The industrial production of beta-lactam antibiotics by fermentation over the past 50 years is one of the outstanding examples of biotechnology. Today, the beta-lactam antibiotics, particularly penicillins and cephalosporins, represent the world's major biotechnology products with worldwide dosage form sales of approximately 15 billion US dollars or approximately 65% of the total world market for antibiotics. Over the past five decades, major improvements in the productivity of the producer organisms, Penicillium chrysogenum and Acremonium chrysogenum (syn. Cephalosporium acremonium) and improved fermentation technology have culminated in enhanced productivity and substantial cost reduction. Major fermentation producers are now estimated to record harvest titers of 40-50 g/l for penicillin and 20-25 g/l for cephalosporin C. Recovery yields for penicillin G or penicillin V are now >90%. Chemical and enzymatic hydrolysis process technology for 6-aminopenicillanic acid or 7-aminocephalosporanic acid is also highly efficient (approximately 80-90%) with new enzyme technology leading to major cost reductions over the past decade. Europe remains the dominant manufacturing area for both penicillins and cephalosporins. However, due to ever increasing labor, energy and raw material costs, more bulk manufacturing is moving to the Far East, with China, Korea and India becoming major production countries with dosage form filling becoming more dominant in Puerto Rico and in Ireland.

Recombinant Acremonium chrysogenum strains for the industrial production of cephalosporin.

Conventional strain improvement programs based on random mutagenesis and rational screening have meant valuable results to the antibiotic producing companies. The development of recombinant DNA techniques and their applications to the industrially-used cephalosporin-producing fungus Acremonium chrysogenum has provided a new tool, complementary to classical mutation, promoting the design of alternative biosynthetic pathways making it possible to obtain new antibiotics and to improve cephalosporin production. Yield increases have been achieved by increasing the dosage of the biosynthetic genes cefEF (deacetoxycephalosporin C expandase/hydroxylase) and cefG (deacetylcephalosporin C acetyltransferase) or enhancing the oxygen uptake by expressing a bacterial oxygen-binding heme protein (Vitreoscilla hemoglobin). New biosynthetic capacities such as the production of 7-aminocephalosporanic acid (7-ACA) or penicillin G have been achieved through the expression of the foreign genes dao (D-amino acid oxidase) coupled with cephalosporin acylase or penDE(acyl-CoA:6-APA acyltransferase) respectively. Confined manipulation of the above-mentioned recombinant strains must be performed according to standing rules.