1,721,037 research outputs found
Ricerca sulle condizioni ottimali per la produzione di acido gluconico da Aspergillus niger su substrati a base di mosto d'uva
No full textUtilizzazione di mosto d'uva per la sintesi di acido gluconico da Gluconobacter suboxydans
No full textFumaric acid production by Rhizopus arrhizus in solid state fermentation, on agricultural wastes and surplus
No full text
La microflora degli impasti acidi. Identificazione, studio delle interazioni tra batteri lattici e lieviti e prospettive genetiche
No full textHydrolyzable tannins from different plant species: their potential uses in agriculture and biomedical sciences
No full textTannins are distributed in several plant species, organs and tissues, where they play a role in inhibiting microbial decay, thus enhancing material durability. In the hydrolysable tannins (HTs), a carbohydrate molecule (usually D-glucose) is partially or totally esterified with phenolic groups , such as gallic or ellagic acids (gallotannins, GTs; or ellagitannins, ETs). HTs are hydrolyzed by weak acids or bases, and are more easily oxidized than condensed tannins (CTs). In the present work, several different water extracts, high in HTs, obtained from plants such as chestnut (Castanea sativa Mill.), myrtle (Myrtus communis L.) and pomegranate (Punica granatum L.), have been analysed and characterized by HPLC/DAD and HPLC/MS methods. Chestnut whole water extract (13% HTs) was investigated in agriculture as a natural soil acidifier, salinity control agent, phosphate solubilizer, iron complexing agent, and nemastat product. Aqueous extracts of the three plant species were also fractionated using both resins and membranes to recover purified molecules as bio-phenols for testing their antimicrobial activity. Novel HTs extracts exhibited antioxidant and antimicrobial activities, potentially prospecting they could support or even substitute molecules of current clinical use
DNA methylation changes induced by cold in psychrophilic and psychrotolerant naganishia yeast species
No full textThe involvement of DNA methylation in the response to cold stress of two different yeast species (Naganishia antarctica, psychrophilic, and Naganishia albida, psychrotolerant), exhibiting different temperature aptitudes, has been studied. Consecutive incubations at respective optimum temperatures, at 4 °C (cold stress) and at optimum temperatures again, were performed. After Methylation Sensitive Amplified Polymorphism (MSAP) fingerprints a total of 550 and 423 clear and reproducible fragments were amplified from N. antarctica and N. albida strains, respectively. The two Naganishia strains showed a different response in terms of level of DNA methylation during cold stress and recovery from cold stress. The percentage of total methylated fragments in psychrophilic N. antarctica did not show any significant change. On the contrary, the methylation of psychrotolerant N. albida exhibited a nonsignificant increase during the incubation at 4 °C and continued during the recovery step, showing a significant difference if compared with control condition, resembling an uncontrolled response to cold stress. A total of 12 polymorphic fragments were selected, cloned, and sequenced. Four fragments were associated to genes encoding for elongation factor G and for chitin synthase export chaperon. To the best of our knowledge, this is the first study on DNA methylation in the response to cold stress carried out by comparing a psychrophilic and a psychrotolerant yeast species
Studio dei rapporti intercorrenti tra fermenti lattici e lieviti nella fase di lievitazione e loro funzionalità in impasti
No full textRed yeasts and carotenoid production: outlining a future for non-conventional yeasts of biotechnological interest.
No full textCarotenoids are one of the most common classes of pigments that occur in nature. Due to their biological properties, they are widely used in phytomedicine and in the chemical, pharmaceutical, cosmetic, food and feed industries. Accordingly, their global market is continuously growing, and it is expected to reach about US$1.4 billion in 2018. Carotenoids can be easily produced by chemical synthesis, although their biotechnological production is rapidly becoming an appealing alternative to the chemical route, partly due to consumer concerns against synthetic pigments. Among the yeasts, and apart from the pigmented species Phaffia rhodozyma (and its teleomorph Xanthophyllomyces dendrorhous), a handful of species of the genera Rhodosporidium, Rhodotorula, Sporobolomyces and Sporidiobolus are well known carotenoid producers. These are known as ‘red yeasts’, and their ability to synthesize mixtures of carotenoids from low-cost carbon sources has been broadly studied recently. Here, in agreement with the renewed interest in microbial carotenoids, the recent literature is reviewed regarding the taxonomy of the genera Rhodosporidium, Rhodotorula, Sporobolomyces and Sporidiobolus, the stress factors that influence their carotenogenesis, and the most advanced analytical tools for evaluation of carotenoid production. Moreover, a synopsis of the molecular and “-omic” tools available for elucidation of the metabolic pathways of the microbial carotenoids is reported. © 2015, Springer Science+Business Media Dordrecht
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