Valeria Cavazzoni

Production and purification of statins from Aspergillus terreus strains

Lovastatin, mevastatin, pravastatin and monacolin J were produced using Aspergillus terreus strains. Mevastatin (170 mg/l) was obtained at 14 days from the A1 strain, lovastatin (256 mg/l) at 21 days from the A2 strain and pravastatin (270-300 mg/l) at 14 days from both the A1 and A2 strains grown on defatted soybean flour. Similar yields of monacolin J (5-10 mg/l) were detected for both strains. Fermentation carried out by adding glycerol to A1 7-d old cultures gave 244 mg lovastatin/l at 14 days employing whole soybean flour. A new extraction procedure was applied to an A2 19-d old culture on the mycelium and the culture filtrate separately. Recovery yield showed that 83% lovastatin was associated with the mycelium and 17% was free in the culture filtrate.

OCCURRENCE OF SELECTED BACTERIAL GROUPS IN THE FAECES OF PIGLETS FED WITH BACILLUS COAGULANS AS PROBIOTIC

A microbiological analysis of piglet faeces was performed on samples collected from animals fed a diet without any additive, animals fed a diet that contained Bacillus coagulans CNCM I‐1061 as probiotic, and animals fed a diet that contained Zn‐bacitracin. The analysis was carried out in concurrence with a zootechnical trial. Selected bacterial groups (lactic acid bacteria, lactococci, enterococci, aerobic and anaerobic cocci, total and faecal coliforms, clostridia, bacteroides, bifidobacteria) were determined at day 1 and after 1, 4 and 10 weeks of life. Numbers of enterococci, coliforms (especially faecal coliforms) showed a decrease over time with probiotic, more evident than with the antibiotic. Daily administration of B. coagulans allowed this bacterium to become integrated into the enteric microflora where it is transient. These results seem to show a positive effect of B. coagulans addition on cocci and faecal coliforms. We suggest that this probiotic may represent an alternative to antibiotics.

Extracellular K5 Polysaccharide of Escherichia coli: Production and Characterization

The extracellular form of the K5 polysaccharide was produced, purified and characterized from a strain of Escherichia coli, the maximum fermentation yield (320 mg/L) was obtained after 15 h. The polysaccharide, recovered by precipitation with cold ethanol (80%), was purified through a pro cess employing an enzymic deproteination step using fungal protease. Charac terization by TLC and GC chromatography revealed that the K5 was mainly composed of glucuronic acid and N-acetyl-glucosamine. The 13C-NMR spectrum showed the products structure to be the same as that of the K5 capsular polysaccharide described in the literature.

Production and purification of an extracellularly produced K4 polysaccharide from Escherichia coli

SummaryThe production of the K4 polysaccharide was obtained for the first time extracellularly from a strain of Escherichia coli. The set up of the fermentation conditions led to the maximum fermentation yield, as extracellular K4, after 20 h. Purification and characterization of this K4 resulted in 200 mg/L of highly purified K4.

D,L-Carnitine resolution byFusarium oxysporum

SummaryL-Carnitine was obtained in 40% yield from D,L-octanoyl carnitine by enantioselective hydrolysis with a strain ofFusarium oxysporum.

Ammonium lactate from deproteinized alfalfa juice byStreptococcus faecium

SummaryDeproteinized alfalfa juice is a by-product of the mechanical fractionation of alfalfa to obtain protein. In this work the juice was used as the substrate for the production of ammonium lactate (l-lactic acid) by a strain ofStreptococcus faecium. Batch fermentation with a constant pH of 5.8 gave 27.2 g/l of lactic acid (90% conversion and 1.1 g/l/h productivity) and 6×1012 cells/l after 24 h. Semicontinuous fermentation allowed the conversion of 3-times the volume of deproteinized juice after 44 h, finally giving 29.7 g/l of ammonium lactate (99% conversion and 2.5 g/l/h productivity) and 4–6×1012 cells/l.

Extracellular polysaccharide by Bradyrhizobium japonicum: production and characterization

An exopolysaccharide from Bradyrhizobium japonicum has been produced, purified and characterized. It is mainly composed of carbohydrates (86 ± 4.5%) and uronic acids (14 ± 1%). The relative proportions are: carbohy drates—glucose 84%, galactose 14%, mannose 2%; uronic acids—glucuronic 83%, galacturonic 10%, mannuronic 3%, arabinuronic 4%. The IR spectrum in dicates the presence of ether, ester, hydrogen bonds and a β-type bond between the monomers. DSC analysis revealed the presence of two transition peaks: the first in the temperature range 117-153 ° C due to bound water and the second at 292°C due to thermal decomposition of the polymer. Viscosity measure ments of water solutions as a function of polymer concentration in the range 0.33-1% w/w allowed the determination of the consistency coefficient and be haviour index. Taking into account the dependence on temperature, a general relation of viscosity as a function of polymer concentration, temperature and shear rate has been proposed.