Mathematical modeling of growth and alkaloid production in Claviceps purpurea batch fermentation.

An new systematic approach for describing Claviceps purpurea growth and ergot alkaloid production during batch fermentation is presented. The model is based on microbial life, as the main characteristic for microbial development during fermentation process. The aging process of the microorganism is represented by life function, defined in microbial life space. The life space is defined as a measure in which the observer follows the development of a biosystem through physiological and morphological changes of a microorganism. As a consequence of such approach the relativistic theory is recognized. To validate the model developed, a test on growth and alkaloid synthesis data from an industrial batch fermentation was performed.

Activation of ergot alkaloid biosynthesis in prototrophic isolates by Claviceps purpurea protoplast fusion.

Intraspecific protoplast fusions were carried out with active ergocornine-ergokryptine and inactive ergocristine Claviceps purpurea strains and vice versa. The isolated prototrophic strains from both types of crossings produced all three alkaloid types, showing that biosynthesis of distinct alkaloid was activated in an inactive partner strain. The prototrophic isolates were stable on minimal medium but they segregated by subculturing on complete medium. In comparison with the original partner strains, differences in morphological and cytological characteristics were also established.

Metabolic changes in a conidia-induced Claviceps paspali strain during submerged fermentation.

Chemical changes in the mycelium of the conidial Claviceps paspali mutant strain, isolated after gamma irradiation, were followed during the course of submerged fermentation and compared with the mycelial parent strain; both strains are capable of producing simple lysergic acid derivatives. The syntheses of lipids, carbohydrates, phosphates, nucleic acids, proteins, and alkaloids, as well as nutrient uptake, were determined. It was found that conidiation induced by mutagenic treatment was accompanied by a set of changes in the metabolic pattern. In the conidial mutant, the primary and secondary metabolic activities were repressed and the protein to nonprotein compound ratio of the cells was changed in favour of protein compounds.

Developmental studies of Claviceps paspali seed cultures for the submerged production of lysergic acid derivatives.

Metabolic pattern of mycelial Claviceps paspali seed cultures during the submerged cultivation was established. By comparing it with conidial and mycelial Claviceps purpurea strains it was found that the biosynthesis of RNA, DNA, and proteins followed a similar course in all Claviceps strains, so the fall of RNA content in mycelium may be considered a general biochemical indicator for optimally developed inoculum. But, two different patterns of carbohydrate and lipid metabolism were observed one for conidial and one for mycelial strains.

Epimerisation of 3beta-ol to 3alpha-ol steroid alkaloids by Nocardia restrictus.

(22S,25S)-5alpha-tomatanin-3beta-ol, N-acetyl-(22S,25S)-5alpha-tomatanin-3beta-ol, (22R,25R)-5alpha-tomatanin-3beta-ol and (22R, 25S)-22, 26-epimino-5alpha-cholestane-3beta, 16beta, 16beta-diol are transformed by Nocardia restrictus into corresponding 3alpha-ol compounds with yields from 7o to 5%.

Microbial degradation of steroid alkaloids. Effect of nitrogen atom in the side-chain on the microbial degradation of steroid alkaloids.

The microbial dehydrogenation of steroid alkaloids follows the dehydrogenation pattern of steroids until the 3-keto-1,4-diene stage. No side-chain cleavage or degradation of the steroid nucleus is observed. Side-chain cleavage of tomatidine is achieved only by previous induction of side-chain splitting enzymes.