Roberto Ambrosoli

Possible use of Biolog methodology for monitoring yeast presence in alcoholic fermentation for wine-making

Aims:  A research was undertaken to explore the possibility to use Biolog system of microbial metabolic characterization for the monitoring of yeast population evolution during alcoholic fermentation for wine production.

BIOAVAILABILITY AND BIODEGRADATION OF PROSULFOCARB IN SOIL

Active microbial degraders of the herbicide prosulfocarb (PSC) were isolated to evaluate their performance in soil with a view to their use for bioremediation. The isolated cultures (a microbial consortium and a Pseudomonas sp. strain) were active when tested in mineral medium with PSC as the only carbon source, but had an adverse effect on the soil indigenous microflora. Biodegradation in the inoculated soils was thus lower than in the uninoculated soil when only the indigenous microflora was present. Further tests showed that the strong affinity of PSC for soil organic matter affected its bioavailability and hence its biodegradation by the inocula. Bioremediation of PSC contaminated soils could thus be undertaken by biostimulation of indigenous microflora.

Microbial metabolism of fluazifop-butyl.

A microbial mixed culture able to grow on fluazifop-butyl and fluazifop was isolated. Fluazifop degradation by this microbial population was studied either when the herbicide was applied as the sole carbon source or in the presence of a second carbon source (sodium acetate or sodium propionate). The degradation rate was enhanced by sodium propionate. The degradation was found to be stereoselective. The S-enantiomer of fluazifop was degraded at a much higher rate than the R-enantiomer. Fluazifop disappearance was accompanied by formation of three metabolites which were identified by UV, IR, MS and NMR analyses. The metabolites were shown to be: 4-(5-trifluoromethyl-2-pyridyl)oxyphenol, 5-trifluoromethyl-2- hydroxypyridine and 2-(5-trifluoro-methyl pyridyl)hydroxy acetate.

Modelling Biolog profiles' evolution for yeast growth monitoring in alcoholic fermentation.

Aims:  A research was undertaken to explore the possibility to express with suitable mathematical models Biolog metabolic curves obtained for oenological yeasts and to use such models for monitoring yeast growth in alcoholic fermentation.

Indications of the occurrence of enhanced biodegradation of carbofuran in some Italian soils

Abstract The occurrence of carbofuran accelerated biodegradation has been ascertained in two Italian soils utilized for sugarbeet cultivation and treated with the pesticide every other year for 5 years. Control soils with similar agrochemical characteristics but no carbofuran treatment history were also chosen. The results obtained showed that in the treated soils the presence of the active ingredient selected a bacterial population active in carbofuran biodegradation, from which pure cultures belonging to genera Arthrobacter, Pseudomonas, Bacillus, Actinomyces , were isolated. As biodegradation was performed when carbofuran was the only carbon source, the phenomenon was thought to be mainly metabolic.

Cometabolic degradation of acifluorfen by a mixed microbial culture

Laboratory experiments were conducted to study the degradation of acifluorfen 5-[2-chloro-4-(trifluoromethyl)-phenoxyl]-2-nitrobenzoic acid by a mixed microbial population. Concentrations of acifluorfen up to 100 mg/l had no inhibitory effect on the growth of microbial culture. The microorganisms degraded acifluorfen through a cometabolic process in presence of 2-nitrobenzoate. The degradation rate of acifluorfen, determined by liquid chromatography analysis in batch cultures incubated under oxygen-limited conditions were compared. The degradation was slower under oxygen than oxygen-limited conditions. Aminoacifluorfen was produced in both conditions.