Penicillium Solitum Research Articles

Identifying dominant spoilage fungal species and preservative treatments for extending shelf life of whole lotus rhizomes at 4 °C

A preservative for whole lotus rhizome preservation was developed under 4 °C storage in this study. The study included the following steps: Firstly, isolation and identification of spoilage causing fungi of lotus rhizome, and four main spoilage causing fungi were identified, including Penicillium solitum, Geotrichum silvicola, Phytopythium helicoides, and Pseudeurotium zonatum. Secondly, selection of antifungal agent with good inhibitory ability against the above four spoilage causing fungi, finally 0.5 % potassium sorbate was selected considering edible security at the same time. Thirdly, the selection of suitable color fixative according to the indexes of root skin and flesh color differences, and sensory evaluation. The final color fixative composition: EDTA-2Na (8 g/L), ascorbic acid (8 g/L), and d-isoascorbic acid sodium (6 g/L). Finally, the antifungal agent and color fixatives were mixed to make the preservative. Soaked in preservative for 20min, drained and packed into PE bags, vacuumed and stored at 4 °C, the lotus rhizomes could maintain better color, got high sensory score, soluble solids content, and total acid content, and the microbial counts were always lower than the untreated group. The preservative could extend the shelf life of whole lotus rhizome to about 50 d at 4 °C.

Characterization of Culturable Mycobiome of Newly Excavated Ancient Wooden Vessels from the Archeological Site of Viminacium, Serbia.

Two ancient wooden vessels, specifically a monoxyle (1st century BCE to 1st century CE) and shipwreck (15th to 17th century CE), were excavated in a well-preserved state east of the confluence of the old Mlava and the Danube rivers (Serbia). The vessels were found in the ground that used to be river sediment and were temporarily stored within the semi-underground exhibition space of Mammoth Park. As part of the pre-conservation investigations, the primary aim of the research presented was to characterize the culturable mycobiomes of two excavated wooden artifacts so that appropriate conservation procedures for alleviating post-excavation fungal infestation could be formulated. Utilizing culture-based methods, a total of 32 fungi from 15 genera were identified, mainly Ascomycota and to a lesser extent Mucoromycota sensu stricto. Soft-rot Ascomycota of genus Penicillium, followed by Aspergillus and Cephalotrichum species, were the most diverse of the isolated fungi. Out of a total of 38 isolates, screened on 7 biodegradation plate assays, 32 (84.21%) demonstrated at least one degradative property. Penicillium solitum had the highest deterioration potential, with a positive reaction in 5 separate plate assays. The obtained results further broaden the limited knowledge on the peculiarities of post-excavation soft-rot decay of archaeological wood and indicate the biochemical mechanisms at the root of post-excavation fungal deterioration.

Introducing Autochthonous Bacterium and Fungus Composition to Enhance the Phytopathogen-Suppressive Capacity of Composts against Clonostachys rosea, Penicillium solitum and Alternaria alternata In Vitro

Given their numerous positive characteristics, composts are widely used agriculturally in sustainable development and resource-saving technologies. The management of phytopathogen-suppressive potential and the fertilizing capacity of composts are of great interest. This study examines the impact of introducing the autochthonous compost species Bacillus subtilis, B. amyloliquefaciens, Pseudomonas aeruginosa, and Aspergillus corrugatus, both individually and in combination, to composts containing dry matter comprising 36% solid compost and 7% compost suspensions to study their phytopathogen-suppressive and phytostimulation activity. The test phytopathogens were Clonostachys rosea, Penicillium solitum, and Alternaria alternata. This is the first report on compost’s potential to biologically control C. rosea and P. solitum. Classical microbiological and molecular biological methods were used to evaluate the survival rate of microorganisms in compost and validate these results. Test plant (Raphanus sativus) germination indexes were determined to evaluate the phytotoxic/phytostimulation effects of the substrates. To assess the effectiveness of biocontrol, mycelial growth inhibition was measured using in vitro tests. The introduction of composition increased the composts’ fertilizing properties by up to 35% and improved antagonistic activity by up to 91.7%. Autochthonous bacterial–fungal composition can promote resistance to fungal root and foliar phytopathogens and raise the fertilizing quality of compost.

Penicopeptide A (PPA) from the deep-sea-derived fungus promotes osteoblast-mediated bone formation and alleviates ovariectomy-induced bone loss by activating the AKT/GSK-3β/β-catenin signaling pathway

The potential of marine natural products as effective drugs for osteoporosis treatment is an understudied area. In this study, we investigated the ability of lead compounds from deep-sea-derived Penicillium solitum MCCC 3A00215 to promote bone formation in vitro and in vivo. We found that penicopeptide A (PPA) promoted osteoblast mineralization among bone marrow mesenchymal stem cells (BMSCs) in a concentration-dependent manner, and thus, we selected this natural peptide for further testing. Our further experiments showed that PPA significantly promoted the osteogenic differentiation of BMSCs while inhibiting their adipogenic differentiation and not affecting their chondrogenic differentiation. Mechanistic studies showed that PPA binds directly to the AKT and GSK-3β and activates phosphorylation of AKT and GSK-3β, resulting in the accumulation of β-catenin. We also evaluated the therapeutic potential of PPA in a female mouse model of ovariectomy-induced systemic bone loss. In this model, PPA treatment prevented decreases in bone volume and trabecular thickness. In conclusion, our in vitro and in vivo results demonstrated that PPA could promote osteoblast-related bone formation via the AKT, GSK-3β, and β-catenin signaling pathways, indicating the clinical potential of PPA as a candidate compound for osteoporosis prevention.

First identification of potato tuber rot caused by Penicillium solitum, its silver nanoparticles synthesis, characterization and use against harmful pathogens.

Potato is one of the highly consumed vegetable crop grown in different regions across Pakistan that is affected by fungal diseases. The current research was conducted to identify fungal pathogen causing mold-like disease of potato in Khyber Pakhtunkhwa (KP), Pakistan. For molecular identification and characterization of the fungal disease; potato tuber samples were collected followed by culturing on potato dextrose agar (PDA). Based on morphological features, the pathogen was identified as a Penicillium species. This result was obtained in 45 different isolates from potato tubers. Molecular identification was done using β-tubulin primers and ITS5 sequencing of 13 different isolates that releveled 98% homology with BLAST (GenBank accession no. KX958076) as Penicillium solitum (GenBank accession nos. ON307317; ON307475 and ON310801). Phylogenetic tree was constructed that showed Penicillium solitum prevalence along with Penicillium polonicum and Penicillium citrinum on potato tubers. Based on this, Penicillium solitum based silver nanoparticles (Ag NPs) were synthesized and characterized using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX) and field emission scanning electron microscopy (FE SEM). UV-analysis showed a characteristic peak at 410 nm confirming synthesis of Penicillium solitum based Ag NPs. This was further confirmed by XRD followed by EDX and SEM that showed face cubic crystal structure with Ag as major constituent of 18 nm formed spherical Ag NPs. FTIR showed band stretching of O-H, N-O and C-H of biological origin. Similarly, Penicillium solitum based Ag NPs presented strong anti-bacterial and anti-fungal activity at 0.5 level of significance LSD. According to our knowledge, this is the first report of Penicillium solitum identification in Pakistan, its Ag NPs synthesis and characterization to be used against pathogens of agricultural significance.

Bacterial-fungal interactions promote parallel evolution of global transcriptional regulators in a widespread Staphylococcus species.

Experimental studies of microbial evolution have largely focused on monocultures of model organisms, but most microbes live in communities where interactions with other species may impact rates and modes of evolution. Using the cheese rind model microbial community, we determined how species interactions shape the evolution of the widespread food- and animal-associated bacterium Staphylococcus xylosus. We evolved S. xylosus for 450 generations alone or in co-culture with one of three microbes: the yeast Debaryomyces hansenii, the bacterium Brevibacterium aurantiacum, and the mold Penicillium solitum. We used the frequency of colony morphology mutants (pigment and colony texture phenotypes) and whole-genome sequencing of isolates to quantify phenotypic and genomic evolution. The yeast D. hansenii strongly promoted diversification of S. xylosus. By the end of the experiment, all populations co-cultured with the yeast were dominated by pigment and colony morphology mutant phenotypes. Populations of S. xylosus grown alone, with B. aurantiacum, or with P. solitum did not evolve novel phenotypic diversity. Whole-genome sequencing of individual mutant isolates across all four treatments identified numerous unique mutations in the operons for the SigB, Agr, and WalRK global regulators, but only in the D. hansenii treatment. Phenotyping and RNA-seq experiments highlighted altered pigment and biofilm production, spreading, stress tolerance, and metabolism ofS. xylosus mutants.Fitness experiments revealed antagonistic pleiotropy, where beneficial mutations that evolved in the presence of the yeast had strong negative fitness effects in other biotic environments. This work demonstrates that bacterial-fungal interactions can have long-term evolutionary consequences within multispecies microbiomes by facilitating the evolution of strain diversity.

Antifungal properties of whey fermented by lactic acid bacteria in films for the preservation of cheese slices

Fungal deterioration by Penicillium species in refrigerated storage conditions is one of the main risk factors for health issues and food waste in the dairy industry. The purpose of this study was to evaluate the antifungal properties of a plastic film carrying whey fermented by lactic acid bacteria (LAB). The results evidenced that a film containing whey fermented using lactic acid bacteria inhibited the growth of Penicillium commune, Penicillium verrucosum and Penicillium solitum for 23, 20 and 17 days, respectively.

Evaluating the potential of lignosulfonates and chitosans as alfalfa hay preservatives using in vitro techniques.

Our objectives were to compare the antifungal activity of 5 lignosulfonates, and 2 chitosans against fungi isolated from spoiled hay, and assess the effects of an optimized lignosulfonate, chitosan, and propionic acid (PRP) on high-moisture alfalfa hay. In experiment 1, we determined the minimum inhibitory concentration and minimum fungicidal concentration of 4 sodium lignosulfonates, 1 magnesium lignosulfonate, 2 chitosans, and PRP (positive control) against Aspergillus amoenus, Mucor circinelloides, Penicillium solitum, and Debaromyces hansenii at pH 4 and 6. Among sodium lignosulfonates, the one from Sappi Ltd. (NaSP) was the most antifungal at pH 4. However, chitosans had the strongest fungicidal activity with the exception of M. circinelloides at both pH 4 and 6. PRP had more antifungal effects than NaSP and was only better than chitosans for M. circinelloides. In experiment 2, we evaluated the effects of 3 additives (ADV): optimized NaSP (NaSP-O, UMaine), naïve chitosan (ChNv, Sigma-Aldrich), and PRP on high-moisture alfalfa hay. The experimental design was a randomized complete block design replicated 5 times. Treatment design was the factorial combination of 3 ADV× 5 doses (0, 0.25, 0.5, 1, and 2% w/w fresh basis). Additives were added to 35 g of sterile alfalfa hay (71.5 ± 0.23% DM), inoculated with a mixture of previously isolated spoilage fungi (5.8 log cfu/fresh g), and aerobically incubated in vitro for 23 d (25°C). After incubation, DM losses were reduced by doses as low as 0.25% for both NaSP-O and PRP (x¯=1.61) vs. untreated hay (24.0%), partially due to the decrease of mold and yeast counts as their doses increased. Also, hay NH3-N was lower in NaSP-O and PRP, with doses as low as 0.25%, relative to untreated hay (x¯=1.13 vs. 7.80% of N, respectively). Both NaSP-O and PRP increased digestible DM recovery (x¯=69.7) and total volatile fatty acids (x¯=94.3), with doses as low as 0.25%, compared with untreated hay (52.7% and 83.8 mM, respectively). However, ChNv did not decrease mold nor yeast counts (x¯=6.59 and x¯=6.16 log cfu/fresh g, respectively) and did not prevent DM losses relative to untreated hay. Overall, when using an alfalfa hay substrate in vitro, NaSP-O was able to prevent fungal spoilage to a similar extent to PRP. Thus, further studies are warranted to develop NaSP-O as a hay preservative under field conditions.

Impact of water activity on the radial growth of fungi in a dairy environment

Filamentous fungi are used in the dairy industry as adjunct cultures in fermented products, but can also lead to food spoilage, waste and economic losses. The control of filamentous fungi with abiotic factors contributes to longer food shelf life and prevention of fungal spoilage. One of the main abiotic factors for controlling fungal growth in foods is water activity (aw). This study aimed to evaluate radial growth as a function of aw for sixteen fungal adjuncts and/or spoilers isolated from dairy products or a dairy environment. Glycerol (a non-ionic compound) and sodium chloride (NaCl, an ionic compound) were used to adjust the aw of culture media. This study showed significant diversity in the responses of the tested fungal strains as a function of medium aw. The growth response of Penicillium bialowiezense and Sporendonema casei was binary, with no clear decrease of growth rate until the growth limit, when the aw was reduced. For the strains of Bisifusarium domesticum, Mucor circinelloides and Penicillium camemberti, a decrease of aw had the same impact on radial growth rate regardless of the aw belonging to their growth range. For the strains of Aspergillus flavus, Cladosporium herbarum, Geotrichum candidum, Mucor lanceolatus, Penicillium expansum, Penicillium fuscoglaucum, Penicillium nalgiovense, Paecilomyces niveus, Penicillium roqueforti, Penicillium solitum and Scopulariopsis asperula, the impact of a decrease in aw was more pronounced at high aw than at low aw. A mathematical model was suggested to describe this impact on the radial growth rate. For all tested species, radial growth was more sensitive to NaCl than glycerol. The ionic strength of NaCl mainly explains the difference in the effects of the two solutes.

First report of blue mold caused by Penicillium polonicum on apple in the United States.

Apples (Malus domestica, Rosaceae) are one of the most widely grown and economically valuable fruits worldwide. In Hood River County, Oregon in 1991 decayed apples exhibiting blue mold signs and symptoms were collected and spores from the causal agent of the disease were isolated. The decayed area of the infected apples was brown colored with soft, decayed tissue, which had bluish-green colored spores on the fruit surface. The whole genome of this isolate was sequenced (GenBank number: JYNM00000000) and it was originally identified as Penicillium solitum strain RS1 (Yu et al. 2016). Subsequent genome-wide species-level investigations showed higher homology to P. polonicum. Therefore, we taxonomically and phylogenetically reevaluated the fungus in question. Colonies were analyzed growing on potato dextrose agar (PDA), Czapek yeast autolysate agar (CYA) and malt extract agar (MEA) at 25°C. Colonies on PDA were blue-green and growth was moderately deep and raised at the center with low margins. Colonies on CYA were blue-green. The range of the colony diameter after 7 days at 25ºC was 24-27 mm on CYA and 20-25 mm on MEA. Colony reverse color on CYA was yellow-brown and on MEA was cream. Conidiophores were terverticillate. Stipes were septate with smooth walls and measured 62-250 × 3-5 µm, x̄ = 111.1 × 3.8 µm with 1-4 branches per stipe. Branches measured 8-25 × 2-6 µm, x̄ = 4.9 × 16.3 µm with 2-4 metulae per branch. Metulae measured 7-14 × 2-5 µm, x̄ = 10.1 × 3.6 µm with 1-3 phialides per metulae. Phialides were flask shaped and measured 5-11 × 2-5 µm, x̄ = 7.5 × 3.4 µm. Conidia were globose to subglobose, borne in columns measuring 2.2-5.4 × 2.1-5.3 µm, x̄ = 3.6 × 3.4 µm. Morphologically, the fungal strain RS1 matched the description of Penicillium polonicum K. Zaleski from Bashir et al. (2017), Duduk et al. (2014) and Frisvad and Sampson (2004) with some minor differences. The ITS, TUB and RpB2 sequences of the strain RS1 were extracted from GenBank accession number JYNM00000000. The sequences were then submitted for nucleotide BLAST (NCBI) analysis in GenBank and evaluated. The ITS sequence aligned 100% with the type specimen (CBS 222.28) of P. polonicum (GenBank number: NR_103687). The TUB sequence aligned over 99% with P. polonicum (GenBank numbers: MK450898, MK450935, MK450899). The RpB2 sequences aligned 99.9% or higher with multiple P. polonicum specimens deposited in CBS and CMV (GenBank numbers: MK450847, MK450846, JN985414 and JN985415). Koch's postulates were conducted. Ten apples were wounded with the point of a 16-penny nail, and 10ul of a conidial suspension adjusted to 106 conidia-distilled water/tween solution was added to the wound. Ten separate apples served as a control that were wounded and 10ul of sterile Tween treated water was used to simulate inoculation. None of the control apples developed signs or symptoms of the disease. The inoculated apples all developed typical blue mold symptoms. The fungus was reisolated from the fruit and deemed to be morphologically identical to those of the original RS1, P. polonicum isolate. To the best of our knowledge this is the first report of blue mold caused by P. polonicum in the USA on apples (Farr and Rossman 2021). This information is important for the apple industry for which blue mold is a major problem.

Effects of Temperature and Humidity on Fungal Occurrence in Dried Red Pepper during Storage

Dried red peppers are frequently contaminated with mycotoxins during storage. To determine the effect of storage environments on fungal occurrence and subsequent mycotoxin accumulation in dried red peppers, we monitored red pepper powder and whole fruit samples for fungal occurrence under various temperatures and relative humidity (RH) conditions during 340 days. Fungal occurrences fluctuated in both pepper forms throughout the storage but they were higher in pepper powder than whole one, higher under low temperatures (-20°C, 0°C, or 4°C) than others (10°C, 25°C, or 30°C), and higher under RH 93% than RH 51% and 69% in both peppers. The samples exhibiting high fungal occurrences were associated mainly with dominant species such as Aspergillus sydowii, Penicillium solitum, P. roqueforti, P. polonicum, or P. chrysogenum. Mycotoxigenic species, including A. flavus, A. ochraceus, A. westerdijkiae, A. tubingensis, and P. citrinum, were also detected throughout the samples. Although mycotoxins were not detected in the samples, mycotoxigenic potential of A. flavus, A. ochraceus, and A. westerdijkiae isolates were confirmed. These results show that low temperatures (-20°C, 0°C, or 4°C) and/or high surrounding RH (>93%) are not safe environments for storage of dried red peppers as fungal growth can occur under these conditions.

Chemical Constituents of the Deep-Sea-Derived Penicillium solitum.

A systematic chemical investigation of the deep-sea-derived fungus Penicillium solitum MCCC 3A00215 resulted in the isolation of one novel polyketide (1), two new alkaloids (2 and 3), and 22 known (4–25) compounds. The structures of the new compounds were established mainly on the basis of exhaustive analysis of 1D and 2D NMR data. Viridicatol (13) displayed moderate anti-tumor activities against PANC-1, Hela, and A549 cells with IC50 values of around 20 μM. Moreover, 13 displayed potent in vitro anti-food allergic activity with an IC50 value of 13 μM, compared to that of 92 μM for the positive control, loratadine, while indole-3-acetic acid methyl ester (9) and penicopeptide A (10) showed moderate effects (IC50 = 50 and 58 μM, respectively).

Low-cost agro-industrial sources as a substrate for the production of l-asparaginase using filamentous fungi

In this paper, Aspergillus caespitosus CCDCA 11593 was first described as a producer of the enzyme l -asparaginase. A new fiber substrate of the Pereskia aculeata Miller was used in solid-state fermentation (SSF) for the production of l -asparaginase. In the submerged fermentation (SbmF), the substrate applied was whey. A total of six filamentous fungi were tested in semi-quantitative tests using the plate method assay to select potential enzyme producers. The most productive ones were Penicillium solitum with sucrose, pH 7.0 and 96 h of culture (0.0410 U.mL −1 ), Aspergillus caespitosus with glucose, pH 6.0, and 96 h of culture (0.0960 U.mL −1 ), and Aspergillus oryzae with sucrose, pH 7.0, and 24 h of culture (0.0388 U.mL −1 ). From these results, A. caespitosus and A. oryzae were selected as the producers of l -asparaginase using the fibrous residue of Pereskia aculeata Miller as the substrate in SSF and whey as the substrate in SbmF. Three moistening agents were investigated in SSF, namely, tap water, deionized water, and Khanna salts. In the production of l -asparaginase in SbmF with whey, A. caespitosus presented 0.0249 U.mL −1 and A. oryzae 0.0139 U.mL −1 of enzyme activities. l -asparaginase produced by A. caespitosus in SSF using P. aculeata's Miller leaf fiber displayed two bands of proteins obtained from SDS-PAGE, 57 kDa and 45 kDa. As substrates, the leaf fiber of P. aculeata Miller and whey were found to be efficient and low-cost for the production of l -asparaginase. • Pereskia aculeata residue as a low-cost substrate for L-asparaginase production in solid-state (SSF) and submerged (SbmF) fermentation systems. • Aspergillus caespitosus is being described for the first time as an l -asparaginase producer. • A high added-value product with application in the pharmaceutical and food fields can be obtained from an alternative low-cost carbon source.

Suitability of FTIR to distinguish pure cultures of problematic mould species from closely related species in the meat industry.

The aim of the study was to apply Fourier Transform Infrared spectroscopy (FTIR) as a rapid screening method for moulds in a specific food production environment (cured meat) and to evaluate whether the method was sufficiently accurate to distinguish Penicillium species that constitute a hazard for the food quality and safety (Penicillium solitum and Penicillium nordicum) from closely related species. FTIR was applied to classify the indigenous mycobiota of two production sites for dried and cured meat products in Norway. Results showed that FTIR was suitable to analyse large amounts of data. While correct classification rates varied depending on the species, overall results indicated that FTIR was able to distinguish the undesired mould species P. solitum and P. nordicum from other species and may hence present an option for rapid screening of large numbers of samples to identify changes in mould composition on site. FTIR presents a potential method for detecting changes in levels of undesired fungi in meat-processing environments. This is the first study that applies FTIR to a specific food production environment and it increases the knowledge on both possibilities and limitations of the method in classification of fungi.

Solitumergosterol A, a unique 6/6/6/6/5 steroid from the deep-sea-derived Penicillium solitum MCCC 3A00215.

A unique C30 steroid, solitumergosterol A (1), was isolated from the deep-sea-derived fungus Penicillium solitum MCCC 3A00215. The planar structure and relative configuration of 1 were established mainly on the basis of extensive analysis of its 1D and 2D NMR as well as HRESIMS data, while its absolute configuration was clarified by comparison of the experimental and theoretical ECD spectra. Noteworthily, 1 is a Diels-Alder adduct of a heterogeneous steroid bearing a 6/6/6/6/5 pentacyclic carbon skeleton. Solitumergosterol A (1) exhibited weak in vitro anti-tumor activity against MB231 cells by a RXRα-dependent mechanism.

Efficient Reduction of Food Related Mould Spores on Surfaces by Hydrogen Peroxide Mist.

The aim of the study was to evaluate the fungicidal effect of a H2O2 mist generating system for disinfection of spores of six food-related moulds (Alternaria alternata, Aspergillus flavus, Geotrichum candidum, Mucor plumbeus, Paecilomyces variotii, and Penicillium solitum) dried on stainless steel. Exposure to H2O2 mist for 2 or 4 h lead to >3 log reduction in mould spores in the majority of the tests. The presence of the soils 2% skim milk or 3% BSA did not significantly alter the fungicidal effect, while the presence of raw meat juice had an adverse fungicidal effect against Penicillium and Mucor in two out of three tests. Fungicidal suspension tests with liquid H2O2 confirmed the effectiveness of H2O2 on reducing the mould spores. Both the surface test and the suspension test indicated that P. variotii is more resistant to H2O2 compared to the other moulds tested. The study shows the efficiency of H2O2 mist on reducing food-related mould spores on surfaces.

Diversity, ecology, and bioprospecting of culturable fungi in lakes impacted by anthropogenic activities in Maritime Antarctica.

In this study, we accessed culturable fungal assemblages present in the sediments of three lakespotentially impacted anthropogenically in the Fildes Peninsula, King George Island, Antarctica and identified 63 taxa. Cladosporium sp. 2, Pseudeurotium hygrophilum, and Pseudogymnoascus verrucosus were recovered from the sampled sediments of all lakes. High concentrations of metals and the lowest fungal diversity indices were detected in the sediments of the Central Lake, which can be influenced by human activities due to their proximity to research stations to those of the other two lakes, which were far from the Antarctic stations. At least one type of biological activity was demonstrated by 40 fungal extracts. Among these, P. hygrophilum, P. verrucosus, Penicillium glabrum, and Penicillium solitum demonstrated strong trypanocidal, herbicidal, and antifungal activities. Our results suggest that an increase of the anthropogenic activities in the region might have affected the microbial diversity and composition. In addition, the fungal diversity in these lakes may be a useful model to study the effect of anthropogenic activities in Antarctica. We isolated a diverse group of fungal taxa from Antarctic lake sediments, which have the potential to produce novel compounds for the both the medical and agriculture sectors.

Highly efficient fungal pectinase and laccase producers among isolates from flax retting liquor

The retting of flax straw depends on specific enzymes capable to separate the fibers from the plant straw. Among these enzymes pectinase and laccase play the most significant part of the process. In a previous study, the bacterial pectinase was studied to assess its role in decolouring and degumming of flax straw. In this study, the fungal pectinase and laccase were evaluated in relation to the flax retting and fiber quality. Ten fungi isolated were obtained from the flax retting chamber. These isolates were identified to species level by Biolog. The results showed that every isolate belonged to certain fungal species. The species are as follow: Aspergillus terricola, Aspergillus parasiticus, Aspergillus pulverulentus, Cladosporium herbarum, Fusarium udum, Penicillium solitum, Rhizopus microspores, Gliocladium catenulatum, Fusarium culmorum and Aspergillus flavus. Pectinase activity of members of these fungal species was determined using well plate and DNS methods while, laccase activity was assessed by DMP method. The fungal strain Aspergillus pulverulentus, F23 gave the highest pectinase activity. This fungus produced 25.78 pectinase Unit/gram fungal biomass. The fungal strain Fusarium udum, F25 gave the highest laccase specific activity (0.930 U/mg) and resulted in increase of biomass accumulation (2.94 g/l). Strain Aspergillus flavus, F30 was active in producing of both pectinase and laccase enzymes at the same time. The specific activity of these enzymes was 89.54 and 0.840 U/mg respectively. The fungal specific activities of pectinase and laccase were determined throughout 15 days of incubation. The highest pectinase activity was noted with Aspergillus pulverulentus after 4 days of incubation resulting in pectinase specific activity of 2.265 U/ml, whereas this fungal strain and Fusarium udum, F25, were the highest in laccase production after 4 days of incubation. Optimization pectinase enzyme production was performed in relation to media pH and temperature of incubation. The storage stability of pectinase was also assessed.

Water-Soluble Glutamic Acid Derivatives Produced in Culture by Penicillium solitum IS1-A from King George Island, Maritime Antarctica.

A new method of screening was developed to generate 770 organic and water-soluble fractions from extracts of nine species of marine sponges, from the growth media of 18 species of marine-derived fungi, and from the growth media of 13 species of endophytic fungi. The screening results indicated that water-soluble fractions displayed significant bioactivity in cytotoxic, antibiotic, anti-Leishmania, anti-Trypanosoma cruzi, and inhibition of proteasome assays. Purification of water-soluble fractions from the growth medium of Penicillium solitum IS1-A provided the new glutamic acid derivatives solitumine A (1), solitumine B (2), and solitumidines A-D (3-6). The structures of compounds 1-6 have been established by analysis of spectroscopic data, chemical derivatizations, and vibrational circular dichroism calculations. Although no biological activity could be observed for compounds 1-6, the new structures reported for 1-6 indicate that the investigation of water-soluble natural products represents a relevant strategy in finding new secondary metabolites.

Occurrence of filamentous fungi isolated from matured blue cheese

Abstract Matured blue cheese can be made from cow's milk associated with the inoculated fungus Penicillium roqueforti, which guarantees specific sensorial characteristics. Recently, Brazil’s fine cheese production and consumption have increased by more than 200%, highlighting the relevance of microbiological quality control of these products. Fungal contaminations are responsible for significant losses in cheese production and provide a suitable environment for mycotoxins production, constituting a hazard to public health. In this work, we evaluated the mycological contamination profile of matured blue cheeses commercialized in Brazil. Samples of ten different brands were analyzed by serial dilution method, by plating in the Dicloran Rose of Bengal Chloramphenicol (DRBC) culture medium and Dicloran Glycerol Medium Base (DG18). Subsequently, different fungi morphotypes were isolated and morphologically identified. As a result, 461 fungi were isolated and identified, notably Aspergillus aculeatus, Penicillium roqueforti and Penicillium solitum. All samples were contaminated by filamentous fungi, amongst those, many already reported as mycotoxin producers, which underlines the relevance of microbiological monitoring.