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The environmental pollution caused by chemical dyes is a growing concern nowadays. Limitations of traditional methods opened the route for nanotechnology; owing to the versatile properties of nanomaterials, gold nanoparticles (AuNPs) became a potential strategy for different applications. In the present study, biosynthesis of gold nanoparticles (BioAuNPs) was carried out by reacting chloroauric acid (HAuCl 4 ) with cell-free filtrate of Penicillium rubens sp. nov. NCIM 1937. The AuNPs were then characterized by UV-visible spectroscopy, HR-TEM, FTIR, and DLS analysis to further examine their efficacious biosynthesis and morphological properties including size, shape, and stability. The biogenic AuNPs are polydisperse in nature, with a mean size of 14.92 ± 5 nm. These AuNPs exhibited promising antimicrobial activity against Escherichia coli NCIM-2065, Bacillus subtilis NCIM-2010, and Penicillium verrucosum MTCC 4935. In vitro quantitative HPLC results revealed that BioAuNPs significantly inhibited the biosynthesis of ochratoxin A (OTA). Microbial fuel cells (MFCs) are intriguing for power generation and wastewater treatment since they can directly transform chemical energy stored in organic matter to electricity by extracellular electron transfer (EET) via membrane proteins. AuNPs also showed excellent potential for dye degradation of organic pollutants, viz., methylene blue (MB), phenol red (PR), bromothymol blue (BTB), Congo red (CR), and 4-nitrophenol (4-NP). All dye removal efficiencies were estimated and fitted to pseudo-first-order processes using kinetic rate constants (Ka).The present study reveals a simple, original, and eco-friendly method for the synthesis of multifunctional biogenic AuNPs that could be effective in OTA detoxification in food products and organic pollutant removal during wastewater treatment for a sustainable environment., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The aim of this study was to investigate the effect of synthetic detergent Merix (Henkel, Kruševac, Serbia), and its particular components-ethoxylated oleyl-cetyl alcohol and sodium tripolyphosphate on the growth and metabolic activity of Penicillium verrucosum. During 19 days of fungal cultivation in Czapek-Dox liquid medium supplemented with or without 0.5% pollutants, the following parameters were observed: pH, the total biomass dry weight, the quantity of free and total organic acids and proteolytic activity. The detergent caused a slight stimulatory (2.41%) effect whereas sodium tripolyphosphate and ethoxylated oleyl-cetyl alcohol provided a slight inhibitory action (0.59 and 2.75%, respectively) on the fungal biomass. The pollutants decreased pH values of the media and the quantity of free organic acids. In contrast, they enhanced the quantity of total organic acids. Proteolytic activity remained nearly unchanged (95.8%) in the presence of detergent and reduced to 80.1% in sodium tripolyphosphate-supplemented medium. In contrast, the enzyme activity sharply increased (260.8%) with ethoxylated oleyl-cetyl alcohol. The obtained results indicate the potential of P. verrucosum in bioremediation of environment contaminated with synthetic detergent taken in high concentration. [ABSTRACT FROM AUTHOR]

Growth of undesirable moulds is one of the major causes of defects in modern cheese production, and it is necessary to discover natural antifungal substances that are non-toxic to humans. Saffron spice has been successfully used as a new ingredient in some Italian or Spanish cheeses, but transference of safranal (the main compound responsible for saffron aroma) during cheesemaking has not yet been studied. In this study, the distribution of safranal in cheese, whey and requesón (Spanish whey cheese) and the antifungal potential of whey fractions against the mould Penicillium verrucosum were studied. To this end, a duplicate fabrication of cheeses was performed with raw ewe's milk with the addition of 40 μg safranal.kg −1 or control milk (no safranal addition). Safranal was more concentrated in cheese and requesón (78.91 and 76.95 μg.kg −1, respectively) than in whey and requesón whey (35.19 and 34.64 μg.kg −1, respectively). These liquid fractions showed good antifungal properties and inhibited mould with a safranal concentration of around 35 μg.kg −1, while a solution of 80 μg.kg −1 was required for a standard safranal solution to obtain a similar inhibition. These results reveal that whey has a synergistic effect with safranal in preventing cheese spoilage by moulds, which encourages making full use of this problematic by-product. [ABSTRACT FROM AUTHOR]

Extracellular β-glucosidase was produced using coffee pulp as a sole carbon source by Penicillium verrucosum by solid state fermentation and 897.36±59 U/g enzyme activity was obtained. Increase in 2.21-fold of enzyme activity on optimizing the bioprocess parameters by response surface methodology based on central composite rotatable design is illustrated. Maximum production level of 1,991.17 U/g was obtained with optimum values of pH 4.2, moisture 66.8%, and fermentation duration of 56 h. The enzyme was partially purified and the enzyme activity was optimum at 50°C temperature and at pH 6. The metal ions such as Mg, Zn, Ca, K, detergents, and chelator such as EDTA were effective and further increased the β-glucosidase activity. On application of β-glucosidase for simultaneous saccharifiation and fermentation, 3.3% ethanol was obtained. Thus, this study provides insight on exploitation of P. verrucosum for synthesis of of β-glucosidase using coffee pulp which is available abundantly in coffee processing industries. [ABSTRACT FROM AUTHOR]

Light has a profound influence on ochratoxin biosynthesis by Penicillia. When incubated under constant daylight of a certain intensity, ochratoxin A biosynthesis is decreased by about 20–30% compared to incubation under constant darkness. Under day/night oscillation, the ochratoxin A polyketide synthase gene, a key gene of the ochratoxin A biosynthesis pathway, is rhythmically expressed, and moreover, the amount of ochratoxin also oscillates between the amounts produced either during constant darkness or during constant light. This indicates a partial degradation of ochratoxin A (20–30%) under light conditions until a certain lower limit is reached. This behavior is dependent on the light intensity. At 1,600 Lux, only weak effects could be observed; however, at 2,800 Lux, the effects became significant. After growth under constant light conditions, Penicillium produced ochratoxin B at amounts which are 5 times higher than after growth in constant dark or in alternating light/dark conditions. Growth experiments in the dark on medium with increasing amounts of ochratoxin A revealed that externally applied ochratoxin is moderately toxic. However, if the same growth experiments are carried out under light conditions, the growth inhibiting activity of ochratoxin A is greatly increased, indicating that light amplifies the toxic activity of ochratoxin. Because of the oscillation of the concentration of ochratoxin A during night and day incubation, Penicillium seems to have developed an adaptive mechanism to reduce the amount of ochratoxin A during daylight below a toxic level. [ABSTRACT FROM AUTHOR]

A putative ochratoxin A (OTA) biosynthetic gene cluster in P. nordicum has been identified. The first part of the gene cluster is located on a DNA fragment of 10 kb in length and harbours three genes. A gene with high homology to an alkaline serine protease gene (accession number AY557343), which represents the upstream border of the cluster. Furthermore the fragment carries a large part (about 2 kb) of the 5′ end of a polyketide synthase ( otapksPN, accession number AY196315) and a complete non-ribosomal peptide synthetase ( otanpsPN, accession number AY534879). The second part of the cluster is located on a 4.3 kb fragment that harbours three open reading frames (ORFs) encoding putative OTA biosynthetic proteins: one incomplete ORF at the 5′ end of the fragment demonstrated homology to an organic anion transporter from rat kidneys ( otatraPN). This transporter has been described to be responsible for the transport of toxic OTA out of the cell. One complete ORF of 951 nucleotides is also located on this fragment. This gene has limited homology to a chloroperoxidase from Gluconobacter oxidans. At the 3′ end of this DNA fragment is an incomplete open reading frame of a potential nitrate transporter. The transcription of all putative OTA biosynthetic genes is increased under OTA conducive conditions. The expression kinetics of the genes resembles that of secondary metabolite biosynthetic genes, in which these genes are co-ordinately expressed during the late growth phase. PCR analysis demonstrated that the gene cluster is only present in the two ochratoxin A producing Penicillium species, P. verrucosum and P. nordicum. P. nalgiovense, a species occurring in the same habitat as P. nordicum carries inactive homologues of the genes. All other species proved to be negative for the genes. This was also true for OTA producing Aspergilli. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the incidence of potential ochratoxigenic mycoflora and ochratoxin A (OA) in poultry, pig and rabbit feeds. Eighty poultry, pig and rabbit feed samples were taken at random from factories located from Córdoba province, Argentina, over a period of 8 months. Isolation and quantitative enumeration of fungal propagules were done on DRBC and DG18 media. The predominant species were A. candidus, A. flavus, A. terreus, A. parasiticus, P. implicatum P. minioluteum, P. crustosum and P. citrionigrum. The distribution of section Nigri species varied according to the feedstuffs analysed. The frequency of A. niger var. niger was noticeably high in poultry feed samples on DRBC medium. The Nigri section species was present at moderate mean colony counts (CFU/g) from three feeds. Mycotoxin analysis of these samples showed that OA was detected in 15%, 10% and 12% of pig, poultry and rabbit feed samples, respectively. The mean levels detected ranged between 15 and 25 ng/g from three feeds. The presence of ochratoxigenic species of Nigri section and OA in feeds indicates the risk of potential exposure of poultry, pigs and rabbits through the ingestion of feeds. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to elucidate the survival of P. verrucosum in infested bulk soil(T1) and infested soil with waste grain (T2). The infested soil and reference soil (T3) was filled into steel cylinders, which were buried and sampled 13 times during a period from October 1994 to March 1996.The abundance of P. verrucosum and indigenous soil fungi were assessed by dilution plating on a selective and diagnostic medium (DYSG). Kernel infection was examined in T2. According to our results, P. verrucosum seems well adapted to survival in arable soil and little affected by indigenous fungi. During the first autumn and winter the grain caused a proliferation of P. verrucosum while its abundance in bulk soil was more constant except for a decrease in February 95, which is ascribed to frost/thaw alternations. In T2, P. verrucosum initially infected more than 50% of the kernels but during the first few months it was ousted by other fungi. A hypothesis regarding waste grain as the natural niche for the fungus in the field was therefore partly rejected. A gradual decrease in the abundance of P. verrucosum in soil during spring, a die-off in the dry summer and aproliferation during the second winter were found in both T1 and T2. Our results cannot provide the reason for the increase during the second winter. On an overall basis, however, they show that P. verrucosum can survive in the field, proliferate on soil organic matter and probably become an integral part of the soil ecosystem. This may constitute a risk of grain contamination when given appropriate environmental conditions. [ABSTRACT FROM AUTHOR]

Our results demonstrate high concentrations of the UV absorbing mycotoxin citrinin in the outer layer of spores from three citrinin-producing strains of Penicillium verrucosum, which is released in an aqueous environment. An important function of the toxin could be to act as a sun protectant in order to create favorable conditions during the initial germination process. When spores from these strains of P. verrucosum were examined by confocal microscopy, a clearly visible fluorescent layer associated with the cell wall was observed. The strains were grown on agar plates, and the mycelial mat was washed with saline. This suspension contained at least 95% of the spores and particulate material, which was removed by filtration after counting the conidia. An aliquot of this filtrate was extracted and citrinin was purified by high pressure liquid chromatography. The absorbance at 319 nm was used to calculate the amount of UV absorbing material released from the spores. Based on the spore numbers in the suspension of the saline extract, we estimated that this material released was 1.4–4.1 pg per spore or 8–24% of the spore weight. Citrinin (and minor amounts of ochratoxin A and some other unidentificable fluorescent compounds) were observed in the filtrate when subjected to thin layer chromatography. [ABSTRACT FROM AUTHOR]

The possible relationship between asparagus decline and the root necrosis potential (RNP) of soil was investigated for 11 asparagus and 4 nonasparagus soils. Asparagus seedlings were grown in each soil in climate chambers. A root necrosis index was used to determine RNP. RNP was correlated with the decline observed in the field for seven white asparagus crops, but not for three white and one green asparagus crops. Low RNP values were obtained from the soils not planted to asparagus. Fusarium oxysporum and F. oxysporum var. redolens accounted for 7070 of the fungi isolated from necrotic roots in RNP tests. Both Fusarium were obtained from all soils. All F. oxysporum and F. oxysporum var. redolens isolates tested were highly virulent on asparagus seedlings in inoculation experiments. F. solani, Penicillium verrucosum var. corymbiferum, and Rhizoctonia violacea were isolated less frequently but were also highly virulent. It is concluded that soil RNP indicated a risk of decline caused by fusaria, but other soil factors were likely to be involved in the aetiology of decline. The study of these factors is necessary to develop a method for the prognosis of decline associated with fusaria. [ABSTRACT FROM AUTHOR]

A part of the gene cluster responsible for the production of ochratoxin A in P. nordicum has been characterised recently. The analysed DNA region contains three putative genes: an alcaline proteinase ( aspPN), a non-ribosomal peptide synthetase ( npsPN) and an polyketide synthase ( otapksPN). The last two genes are putative genes of the ochratoxin A biosynthetic pathway. Interestingly the otapksPN gene is present in this form only in P. nordicum but not in P. verrucosum indicating genetic differences between both ochratoxin A producing Penicillium species. The genes in ochratoxin A producing Aspergillus species seems to be completely different. It has been demonstrated that the npsPN gene is actively transcribed in P. nordicum under ochratoxin A producing conditions, indicating that this gene is involved in ochratoxin A biosynthesis. [ABSTRACT FROM AUTHOR]