V. Krumphanzl

Continuous production of steroid glycoalkaloids by immobilized plant cells

SummaryNon-permeablilized cells ofSolanum aviculare were immobilized by their adsorption and covalent linkage on activated polymeric adsorbent. The retention of extracellular production of steroid glycoalkaloids was studied in a packed-column recycle reactor.

Immobilization of yeast cells with retention of cell division and extracellular production of macromolecules

SummaryWhole cells of a killer strain of Saccharomyces cerevisiae have been covalently linked to the modified hydroxyalkyl methacrylate gel Separon H-1000 E. The occurence of cell division and the killer phenomenon were observed when immobilized cells were incubated in nutrient medium.

Regulation of biosynthesis of monensins on chemically defined medium.

Addition ofL-valine andDL-isoleucine to the cultivation medium ofStreptomyces cinnamonensis was found to affect the ratio of synthesized monensins A and B. In the presence ofL-valine monensin A is synthesized predominantly, whereas in the presence ofDL-isoleucine the production of monensin B increases.

New bacteriophage-like particles in Corynebacterium glutamicum.

Three new phage-like particles (CG1, CG2, and CGK1) were isolated from Corynebacterium glutamicum CBII. Particles CG1 and CG2 are DNA phages with long, noncontractile tails, CGK1 is a killer particle according to electron microscopy. A heat-stable low-molecular-weight bacteriocidal substance affecting various coryneform bacteria was observed to be joined to the killer particle CGK1.

Improving the production of monensin byStreptomyces cinnamonensis

The production of monensin byStreptomyces cinnamonensis was increased by genetic improvement of the strain and by modification of cultivation conditions. The selection of a suitable strain and optimization of the fermantation process (temperature, aeration, addition of esters of oleic acid) resulted in a 30 fold increase of the monensin production.

Isolation of the pMI 10 plasmid from the α-amylase producing strain of Bacillus subtilis

SummaryB. subtilis A 18, a producer of exocellular amylase, was found to carry covalently closed DNA plasmid molecules (pMI 10). The pMI 10 was isolated and characterized by electron microscopy, electrophoretic mobility and restriction endonuclease cleavage pattern. The pMI 10 was absent in all α-amylase low productive or nonproductive clones. The pMI 10 DNA was transformed together with pUB 110 DNA into B. subtilis RM 125 arg-leu- recipient cells, and, hence, compatibility of these plasmids could be demonstrated.

The extracellular system of β-1,3-glucanases ofAlternaria tenuissima andAspergillus vesicolor

During cultivation in a minimal medium with glucoseAlternaria tenuissima andAspergillus vesicolor produce constitutively α- and β-glucanases. Fractions of β-1,3-glucanases exhibiting affinity for laminarin were separated by means of gel filtration chromatography. Two neutral β-1,3-glucanases with affinity for yeast glucan were isolated by affinity chromatography and further characterized.

Biosynthesis ofL-lysine inCorynebacterium glutamicum on sucrose, ethanol and acetic acid

Production ofL-lysine was followed in two lysine-accumulating mutants ofCorynebacterium glutamicum ATCC 13287 in media containing sucrose, ethanol, acetic acid or a mixture of acetic acid and ammonium or sodium acetate. It was found that acetate is the best substitution for sucrose.

Effect of precursors on biosynthesis of monensins A and B

Precursors of monensins (acetate, propionate, butyrate, isobutyrate) affect the total production and the relative proportion of monensins A and B. Addition of propionate into the fermentation medium causes a prevalence of monensin B whereas butyrate and isobutyrate stimulate the production of monensin A and suppress the production of monensin B.

Biosynthesis of Monensins A and B: the Role of Isoleucine

Isoleucine added to the cultivation medium ofStreptomyces cinnamonensis C-10Q-5 induced a relative increase of the production of monensin B at the expense of monensin A.U-14C-Isoleucine was found not to be a specific monensin B precursor. The incorporation of l-13C-2-methylbutyrate into monensins A and B showed the label to be evenly incorporated in both products at carbon atoms originating from C(i) of propionate. In regulatory mutants insensitive to 2-amino-3-cblorobutyrate isoleucine influenced the production of monensins only slightly but strains resistant to 2-aminobutyrate and norleucine decreased their total production by 2—12 % in the presence of isoleucine which was associated with a decrease of monensin A content by 14—52 %. The inhibitory effect of isoleucine on the biosynthesis of valine, a specific precursor of the butyrate unit of monensin A, is discussed.