Search

The antibacterial effect of different glucose oxidase (GOX)/glucose combinations was studied on two food-poisoning organisms, enterotoxic Escherichia coli PM 015 and Salmonella derby BP 177. Growth of E. coli in nutrient broth (NB) was clearly inhibited by 4.0 mg/ml glucose after 24 h when combined with 2.0 U/ml GOX and after 48 h when combined with 0.5 or 1.0 U/ml GOX. Salmonella derby was more resistant than E. coli, but showed clear growth inhibition only after 48 h when inoculated in tubes where 2 mg glucose/ml and 2 U GOX/ml (or 4 mg glucose/ml and 1 U GOX/ml) were combined. In order to understand if the enzyme effect on microbial growth can be attributed to hydrogen peroxide or to pH decrease as a result of the production of gluconic acid, catalase (CAT) was added to GOX/glucose system. Since CAT decomposes H2O2 to H2O and O2, the antibacterial effect was ascribed to a pH decrease as a result of gluconic acid in the system. [ABSTRACT FROM AUTHOR]

Direct ammonium fumarate production from glucose-based media with Rhizopus arrhizus NRRL 1526 was obtained using 2 kmol (NH4)2CO3 per m3 as neutralising agent and controlling mycelial growth by phosphorous (P) limitation. As the P level in the production medium was increased from 0 to 0.3 kg of KH2PO4 per m3, the fumarate yield decreased from 0.32 to 0.13 g per g of glucose consumed; maximum ammonium fumarate productivity (0.46 kg m-3 h-1) was obtained when using 0.1 kg phosphate m-3. [ABSTRACT FROM AUTHOR]

Copyright of Italian Journal of Neurological Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fumaric acid production by Rhizopus arrhizus from potato flour was studied at different initial substrate concentrations (S), C/N ratios and fermentation times ( t f) in a composite design experiment. By using response surface methodology and canonical analysis, the experimental values of fumaric acid and mycelial biomass yields and productivity were fitted to the only statistically significant factors with mean percentage errors of 11, 26 and 13%, respectively. Owing to the limited statistical significance of the C/N ratio, it was possible to determine the values of S (25-50 g/l of glucose equivalent) and t f(44-100 h) associated with fumaric acid yields ranging from 60 to 75% and productivities varying from 6 to 8.4 g/l per day. Since such results were in quite good agreement with previous experiments carried out on other starchy materials, the above operating conditions might be used to minimize fumaric acid production costs as a function of the feed-stock used. [ABSTRACT FROM AUTHOR]

Fifty-eight strains, representing 31 species of Penicillium, were screened for extracellular β-glycosidase (amygdalase/linamarase) and pectolytic (polygalacturonase, pectin lyase) enzymes. One strain each of P. turbatum, P. piceum and P. paxilli showed very high β-glycosidase activity and slightly lower activities were found in P. crustosum, P. expansum, P. oxalicum and P. aurantiogriseum. Generally, maximum β-glycosidase activity showed reached during the stationary phase of growth. The seven species with highest β-glycosidase activity showed different patterns of pectolytic activities, indicating that different species or combinations of species could be selected for different potential applications. [ABSTRACT FROM AUTHOR]

Botryosphaeria rhodina produced β-glucan when grown on undiluted olive-mill wastewaters (OMW). The production of exopolysaccharide increased with the COD up to 17.2 g l-1 on the most loaded OMW (151 and 66 g l-1 of COD and total sugar, respectively). The total phenol content of OMW was reduced from 8 to 4.1 g l-1. [ABSTRACT FROM AUTHOR]

During screening of Penicillium species for extracellular glucose oxidase production, a strain of Penicillium variabile (P16) was selected which released high activities of enzyme into the culture medium. Maximum activity (5.49 U/ml) was after 96 h cultivation in shake-flask culture. [ABSTRACT FROM AUTHOR]

Fungal strains naturally occurring on the wood and leaves of the salt-excreting desert tree Tamarix were isolated and characterized for their ability to produce cellulose- and starch-degrading enzymes. Of the 100 isolates, six fungal species were identified by ITS1 sequence analysis. No significant differences were observed among taxa isolated from wood samples of different Tamarix species, while highly salt-tolerant forms related to the genus Scopulariopsis (an anamorphic ascomycete) occurred only on the phylloplane of T. aphylla. All strains had cellulase and amylase activities, but the production of these enzymes was highest in strain D, a Schizophyllum-commune-related form. This strain, when grown on pretreated Tamarix biomass, produced an enzymatic complex containing levels of filter paperase (414 +/- 16 IU/ml) that were higher than those of other S. commune strains. The enzyme complex was used to hydrolyze different lignocellulosic substrates, resulting in a saccharification rate ofpretreated milk thistle (73.5 +/- 1.2%) that was only 10% lower than that obtained with commercial cellulases. Our results support the use of Tamarix biomass as a useful source of cellulolytic and amylolytic fungi and as a good feedstock for the economical production of commercially relevant cellulases and amylases.