Screening of cultivation media for LDPE biodegradation by Penicillium verrucosum CNM-FP-02

The paper’s aim was to select the optimal mineral medium for LDPE biodegradation by the strain Penicillium verrucosum CNM-FP-02. It was selected 5 mineral salt media (MSM), which differed in salt content and N/P ratio. After 40 days of submerged cultivation, the following parameters were determined: catalase activity and pH of cultural media, biomass accumulation, rate of LDPE degradation, optical microscopy and the tensile testing of polyethylene. It was observed that catalase activity on all media, except MSM 4, was higher in the presence of LDPE. The addition of polyethylene to the growth media stimulated the fungal biomass accumulation by 19.3-93.1% (4 media out of 5 tested). The percentage of degradation of LDPE films was different, depending on the culture medium, from 0.41% to 0.92%. The most active LDPE films were degraded on medium MSM 2. Visualization of plastic strips under an optical microscope revealed the immobilization of the microorganism and the damage on the polyethylene surface. The tensile test showed increased elasticity of the plastic in the variants treated with fungal strain. In conclusion, in order to stimulate the biodegradation of LDPE by the strain P. verrucosum CNM-FP-02, the medium MSM 2 (N/P ratio 1:1) was selected.

Prevalence of toxigenic fungi and mycotoxins in Arabic coffee (Coffea arabica): Protective role of traditional coffee roasting, brewing and bacterial volatiles

Fungal infection and synthesis of mycotoxins in coffee leads to significant economic losses. This study aimed to investigate the prevalence of toxigenic fungi, their metabolites, and the effect of traditional roasting and brewing on ochratoxin A (OTA) and aflatoxins (AFs) contents of naturally contaminated coffee samples. In addition, in vivo biocontrol assays were performed to explore the antagonistic activities of Bacillus simplex 350–3 (BS350-3) on the growth and mycotoxins synthesis of Aspergillus ochraceus and A. flavus. The relative density of A. niger, A. flavus, Penicillium verrucosum and A. carbonarius on green coffee bean was 60.82%, 7.21%, 3.09% and 1.03%, respectively. OTA contents were lowest in green coffee beans (2.15 μg/kg), followed by roasted (2.76 μg/kg) and soluble coffee (8.95 μg/kg). Likewise, AFs levels were highest in soluble coffee (90.58 μg/kg) followed by roasted (33.61 μg/kg) and green coffee (9.07 μg/kg). Roasting naturally contaminated coffee beans at three traditional methods; low, medium and high, followed by brewing resulted in reduction of 58.74% (3.50 μg/kg), 60.88% (3.72 μg/kg) and 64.70% (4.11 μg/kg) in OTA and 40.18% (34.65 μg/kg), 47.86% (41.17 μg/kg) and 62.38% (53.73 μg/kg) AFs contents, respectively. Significant inhibitions of AFs and OTA synthesis by A. flavus and A. carbonarius, respectively, on infected coffee beans were observed in presence of Bacillus simplex BS350-3 volatiles. Gas chromatography mass spectrochemistry (GC-MS/MS) analysis of head-space BS350-3 volatiles showed quinoline, benzenemethanamine and 1-Octadecene as bioactive antifungal molecules. These findings suggest that marketed coffee samples are generally contaminated with OTA and AFs, with a significant level of roasted and soluble coffee contaminated above EU permissible limits for OTA. Further, along with coffee roasting and brewing; microbial volatiles can be optimized to minimize the dietary exposure to mycotoxins.

Utjecaj lokaliteta na sigurnost i kvalitetu slavonske kobasice

Slavonska kobasica je trajna kobasica koje se u seoskim domaćinstvima u Slavoniji proizvodi tradicionalnom tehnologijom, pri kojoj se tijekom zrenja na ovitku proizvoda mogu razviti plijesni. Cilj je ovog rada bio identificirati površinske plijesni i utvrditi njihov utjecaj na kvalitetu i zdravstvenu sigurnost proizvoda, uključujući pojavnost mikotoksina okratoksina A (OTA) i aflatoksina B1 (AFB1). Tijekom rada komunicirano je sa šest proizvodnih lokaliteta na području Slavonije. Pripremljeno je 18 uzoraka slavonske kobasice koje su analizirane na kraju proizvodnog procesa u trajanju od tri mjeseca. Ukupno je identificirano 8 različitih vrsta plijesni, među kojima je dominirao rod Penicillium (88,89 %). Osim šest Penicillium vrsta, izolirana je po jedna vrste iz rodova Aspergillus (8,33 %) i Mucor (2,78 %). Identificirani su i mogući izvori OTA i AFB1, Penicillium verrucosum i Aspergillus flavus, a određena je samo prisutnost OTA i to u koncentraciji od 5,10 μg/kg.

Antimicrobial Properties, Cytotoxic Effects, and Fatty Acids Composition of Vegetable Oils from Purslane, Linseed, Luffa, and Pumpkin Seeds

In the present study, the antimicrobial and cytotoxic activities, as well as the fatty acids composition in vegetable seed oils from linseed, purslane, luffa, and pumpkin were evaluated. For this purpose, two linseed oils and one luffa oil were commercially obtained, while purslane and pumpkin oils were obtained from own cultivated seeds. The results showed a variable fatty acids composition among the tested oils, with α-linolenic, linoleic, oleic, palmitic, and stearic acid being the most abundant compounds. In regards to particular oils, linseed oils were a rich source of α-linolenic acid, luffa and pumpkin oil were abundant in linoleic acid, while purslane oil presented a balanced composition with an almost similar amount of both fatty acids. Luffa oil was the most effective against two of the tested cancer cell lines, namely HeLa (cervical carcinoma) and NCI-H460 (non-small cell lung cancer), while it also showed moderate toxicity against non-tumor cells (PLP2 cell line). Regarding the antibacterial activity, linseed oil 3 and pumpkin oil showed the highest activity against most of the tested bacteria (especially against Enterobacter cloacae and Escherichia coli) with MIC and MBC values similar to the used positive controls (E211 and E224). All the tested oils showed significant antifungal activities, especially luffa and pumpkin oil, and for most of the tested fungi they were more effective than the positive controls, as for example in the case of Aspergillus versicolor, A. niger, and Penicillium verrucosum var. cyclopium. In conclusion, the results of our study showed promising antimicrobial and cytotoxic properties for the studied seed oils which could be partly attributed to their fatty acids composition, especially the long-chain ones with 12–18 carbons.

Atividade antimicrobiana e antibiofilme da Ilex paraguariensis: Uma revisão de literatura

Nos últimos anos, o aumento da busca por alternativas medicinais e nutricionais no campo da saúde ocasionou a busca por plantas presentes no cotidiano da população. Consequentemente, diversas pesquisas almejavam avaliar o potencial e benefícios para a saúde. Portanto, o objetivo do estudo é realizar uma revisão de literatura sobre a potencial utilização medicinal e nutricional da planta Ilex paraguariensis. Foram realizadas pesquisas nas bases de dados PubMed, EMBASE, Biblioteca Virtual de Saúde (BVS), Cochrane Library, Web of Science, utilizando os descritores selecionados no MeSH, DeCs e Entree. As buscas foram realizadas no período de janeiro de 2020. O critério de inclusão utilizado englobava artigos dos últimos 20 anos encluindo revisões de literatura. Após as buscas foram selecionados 12 artigos para compor a revisão de literatura. A Ilex paraguariensis mostrou capacidade de atividade antimicrobiana e antiinflamatória. Os extratos da erva mate foram capazes de inibir os microrganismos: Salmonella enteritidis, Candida albicans, Proteus mirabilis, Pseudomas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus mutans, Listeria monocytogenes, Propionibacterium acnes, Enterobacteri cloacae, Bacillus cereus, Micrococcus flavus, Aspergillus fumigatus, Aspergillus versicolor, Aspergillus ochraceus, Aspergillus niger, Candida crusei, Penicillium funiculosum, Penicillium verrucosum var. ciclopium, Klebsiella pneumoniae, Enterobacter agglomerans, Enterobacter aerogeneses, Serratia marcesens, Proteus mirabilis. Porém, não houve consenso na literatura sobre atividade contra a Escherichia coli, Enterococcus faecalis e Acinetobacter baumannii. Assim, a erva mate apresenta um potencial antimicrobiano sob alguns microrganismos, mas ainda são necessários mais estudos para uma análise mais eficiente sobre a ação contra as bactérias e uma possível aplicação clínica.

Inhibition of Mycotoxigenic Fungi in Different Vegetable Matrices by Extracts of Trichoderma Species

Post-harvest fungal diseases of plant products are a serious concern leading to economic losses and health risks. Moreover, the use of synthetic chemical fungicides to prevent these diseases is limited due to toxic residues. This study aimed at determining the effective dose of extracts of Trichoderma asperellum IMI393899 (TE1) and Trichoderma atroviride TS (TE2) in inhibiting the contamination by mycotoxigenic fungi on different plant matrices. Extracts were tested on tomatoes contaminated by Fusarium verticillioides and Fusarium graminearum, wheat contaminated by Penicillium verrucosum and maize contaminated by Aspergillus flavus. The efficacy of extracts was evaluated at two time intervals after treatment, 4 and 11 days for tomato, and 10 and 20 days for both wheat and maize. Both extracts showed a significant inhibitory activity on mycotoxigenic pathogens and significantly reduced Log CFU/g compared to the control. Moreover, the extracts reduced mycotoxin production in a dose dependent manner and with a long-lasting effect. The ochratoxin A was reduced by both extracts but only the extract TE2 was effective in reducing aflatoxins, whereas TE1 treatment increased their synthesis.

Ozone inactivation of fungi associated with barley grain

The use of ozone as a fungicide for barley storage was studied. The effects of ozone on the inactivation of natural and inoculated fungi on barley were evaluated at different water activities and temperatures. Results indicated that higher ozone doses were better at inactivating the natural fungi on barley than lower ozone doses. An ozone dose of 0.98mg/g • min was able to reduce the natural fungi counts on the barley at 0.98aw by over 97% after 45 minutes of ozone contact time. The inactivation of the natural fungi and Aspergillus flavus on the barley was favoured by higher temperatures. Ozone consumption of the barley was higher at higher temperatures. Tests on A. flavus spores inoculated on barley indicated that they were resistant to ozone doses up to 4.90mg/g while Penicillium, verrucosum spores showed no resistance to any ozone doses that were tested. Inactivation of A. flavus (vegetative state) and P. verrucosum spores were favoured by higher water activities. The effect of ozone on barley germination was also examined. By 15 minutes of treatment at an ozone dose of 0.98mg/g • min, all the fungi tested were inactivated by over 90%, while germination was only reduced by 6%. Different water activities had no effect on the germination of barley. The findings show that ozone may be applied as a fumigant against fungi attacking high moisture content barley and provide the possibility of using it as an alternative to current chemicals for preserving stored barley.

Ozone inactivation of fungi associated with barley grain

The use of ozone as a fungicide for barley storage was studied. The effects of ozone on the inactivation of natural and inoculated fungi on barley were evaluated at different water activities and temperatures. Results indicated that higher ozone doses were better at inactivating the natural fungi on barley than lower ozone doses. An ozone dose of 0.98mg/g • min was able to reduce the natural fungi counts on the barley at 0.98aw by over 97% after 45 minutes of ozone contact time. The inactivation of the natural fungi and Aspergillus flavus on the barley was favoured by higher temperatures. Ozone consumption of the barley was higher at higher temperatures. Tests on A. flavus spores inoculated on barley indicated that they were resistant to ozone doses up to 4.90mg/g while Penicillium, verrucosum spores showed no resistance to any ozone doses that were tested. Inactivation of A. flavus (vegetative state) and P. verrucosum spores were favoured by higher water activities. The effect of ozone on barley germination was also examined. By 15 minutes of treatment at an ozone dose of 0.98mg/g • min, all the fungi tested were inactivated by over 90%, while germination was only reduced by 6%. Different water activities had no effect on the germination of barley. The findings show that ozone may be applied as a fumigant against fungi attacking high moisture content barley and provide the possibility of using it as an alternative to current chemicals for preserving stored barley.

Aspergillus flavus Growth Inhibition and Aflatoxin B1 Decontamination by Streptomyces Isolates and Their Metabolites

Aflatoxin B1 is a potent carcinogen produced by Aspergillus flavus, mainly during grain storage. As pre-harvest methods are insufficient to avoid mycotoxin presence during storage, diverse curative techniques are being investigated for the inhibition of fungal growth and aflatoxin detoxification. Streptomyces spp. represent an alternative as they are a promising source of detoxifying enzymes. Fifty-nine Streptomyces isolates and a Streptomyces griseoviridis strain from the commercial product Mycostop®, evaluated against Penicillium verrucosum and ochratoxin A during previous work, were screened for their ability to inhibit Aspergillus flavus growth and decrease the aflatoxin amount. The activities of bacterial cells and cell-free extracts (CFEs) from liquid cultures were also evaluated. Fifty-eight isolates were able to inhibit fungal growth during dual culture assays, with a maximal reduction going down to 13% of the control. Aflatoxin-specific production was decreased by all isolates to at least 54% of the control. CFEs were less effective in decreasing fungal growth (down to 40% and 55% for unheated and heated CFEs, respectively) and aflatoxin-specific production, with a few CFEs causing an overproduction of mycotoxins. Nearly all Streptomyces isolates were able to degrade AFB1 when growing in solid and liquid media. A total degradation of AFB1 was achieved by Mycostop® on solid medium, as well as an almost complete degradation by IX20 in liquid medium (6% of the control). CFE maximal degradation went down to 37% of the control for isolate IX09. The search for degradation by-products indicated the presence of a few unknown molecules. The evaluation of residual toxicity of the tested isolates by the SOS chromotest indicated a detoxification of at least 68% of AFB1’s genotoxicity.