Penicillium Islandicum Research Articles

Optimization of oxalic acid production by fungi for biotechnological solubilization of rock phosphate

This study describes a biotechnological strategy for producing and applying oxalic acid to solubilize phosphorus (P) from rock phosphate (RP). We evaluated six fungal species (Aspergillus niger FS1, Penicillium islandicum FS41, Pleurotus ostreatus PO1, Rhizoctonia solani Rhiz555, Sclerotium rolfsii Sr25, and Sclerotinia sclerotiorum Scl134) and three culture media (potato dextrose broth, Tsao and Strasser media) to maximize oxalic acid production. Among the fungal isolates tested and culture media, S. rolfsii Sr25 and Tsao medium showed efficient oxalic acid production. Tsao medium was optimized following a response surface methodology after initial screening of factors affecting RP solubilization. The optimized concentrations were 1 g L–1 NaNO3, 100 g L–1 glucose, 2 g L–1 KH2PO4, 4.5 g L–1 yeast extract, and 25 mg L–1 MgSO4·7H2O used for 20 days of incubation. Under these conditions, 71 mmol L–1 oxalic acid was obtained, representing a three-fold increase over production under non-optimized conditions (20 mmol L–1). Under optimized conditions, oxalic acid produced by S. rolfsii Sr25 reacted with low-solubility RP and solubilized 100 % of the P contained in ore. Thus, using S. rolfsii Sr25 to produce oxalic acid seems a promising biotechnological alternative for P solubilization from RP.

Incidence of Post-harvest Blue Mould Rot Disease of Indian Gooseberry (Emblica officinalis Goerth.) Incited by Penicillium islandicum Sopp.

Background: Aonla or Indian gooseberry (Emblica officinalis Goerth. Syn. Phyllanthus emblica L.) is one of the most important indigenous fruit of Indian sub-continent and cultivated since time immemorial. Amongst post-harvest diseases of aonla, blue mould rot caused by Penicillium islandicum Sopp. is most important as it affects the fruit yield and quality pertaining to the market value. Methods: A survey was conducted during November to January 2015-16 to assess the post-harvest practices and losses of Indian gooseberry in four locations of Hisar and Rewari districts of Haryana viz., CCS HAU Hisar orchard, terminal market of Hisar, Regional Research Station, Bawal orchard and terminal market of Rewari. Result: The survey carried out from first fortnight of November to last fortnight of January, 2015-16 revealed that the maximum per cent disease incidence (6 and 7.50%) due to blue mould rot was observed in terminal markets of Rewari and Hisar districts, respectively. The disease incidence was 7.0 and 6.25 per cent in fruits collected from orchards of CCS HAU, Hisar and RRS, Bawal respectively after 10 days of storage in laboratory. Some indigenous postharvest practices were observed being practiced in all the growing areas mostly by the growers and /or traders involved in harvesting.

Marine Fungal Cerebroside Flavuside B Protects HaCaT Keratinocytes against Staphylococcus aureus Induced Damage.

Cerebrosides are glycosylated sphingolipids, and in mammals they contribute to the pro-/anti-inflammatory properties and innate antimicrobial activity of the skin and mucosal surfaces. Staphylococcus aureus infection can develop, not only from minor scratches of the skin, but this pathogen can also actively promote epithelial breach. The effect of cerebroside flavuside B from marine sediment-derived fungus Penicillium islandicum (Aniva Bay, the Sea of Okhotsk) on viability, apoptosis, total caspase activity, and cell cycle in human epidermal keratinocytes HaCaT line co-cultivated with S. aureus, as well as influence of flavuside B on LPS-treated HaCaT cells were studied. Influence of flavuside B on bacterial growth and biofilm formation of S. aureus and its effect on the enzymatic activity of sortase A was also investigated. It was found S. aureus co-cultivated with keratinocytes induces caspase-depended apoptosis and cell death, arrest cell cycle in the G0/G1 phase, and increases in cellular immune inflammation. Cerebroside flavuside B has demonstrated its antimicrobial and anti-inflammatory properties, substantially eliminating all the negative consequences caused by co-cultivation of keratinocytes with S. aureus or bacterial LPS. The dual action of flavuside B may be highly effective in the treatment of bacterial skin lesions and will be studied in the future in in vivo experiments.

Cytoprotective Activity of p-Terphenyl Polyketides and Flavuside B from Marine-Derived Fungi against Oxidative Stress in Neuro-2a Cells.

The influence of p-terphenyl polyketides 1–3 from Aspergillus candidus KMM 4676 and cerebroside flavuside B (4) from Penicillium islandicum (=Talaromyces islandicus) against the effect of neurotoxins, rotenone and paraquat, on Neuro-2a cell viability by MTT and LDH release assays and intracellular ROS level, as well as DPPH radical scavenging activity, was investigated. Pre-incubation with compounds significantly diminished the ROS level in rotenone- and paraquat-treated cells. It was shown that the investigated polyketides 1–3 significantly increased the viability of rotenone- and paraquat-treated cells in two of the used assays but they affected only the viability of paraquat-treated cells in the LDH release assay. Flavuside B statistically increased the viability of paraquat-treated cells in both MTT and LDH release assays, however, it increased the viability of rotenone-treated cells in the LDH release assay. Structure–activity relationships for p-terphenyl derivatives, as well as possible mechanisms of cytoprotective action of all studied compounds, were discussed.

Analytical Study of the Archaeological Leather Document Preserved in Egyptian Museum and New Proposal for Museum Exhibition

This study was done on a piece of archaeological leather document preserved in Egyptian museum storeroom under No.JE90809 SR 5/13677, excavated 1966. The leather document showed different aspects of deterioration types. Different analytical methods were used for identifying the components of the leather document to explain its mechanism of deterioration process. Analytical methods were used: visual assessment, documentation process by high resolution camera and scanner in multispectral imaging (MSI), diagnostic examinations using Multi Spectral Imaging (VIS-UV-IR), isolation and identification of different types of fungi, investigation of the surface morphology and animal type using digital light microscope (Dino light), stereo microscope (S.M.) and polarizing microscope (P.M.), identification of ink binder, amino acids degradation and tanning materials by Fourier transformation infrared spectrophotometry (FTIR) it is a qualitative analysis to give general information concerning collagen, identification of inks by X-ray diffraction (XRD), measuring the thickness by micro meter. In addition to suggest a new method for Museum show for the archaeological leather document as the preparation of a new method of exhibition is considered one of the most important goal of this study, because the current method of exhibition is considered one of the most important reason for the deterioration of the studied document. The results revealed thatthe microscopic examinations of samples clarify that the type of skin used was sheep in comparison with the standard samples. Also it explained the deformation of the appearance, contaminations from stains and dusts, and damages caused by physical factors. X-ray diffraction results showed that the ink used was made of carbon black ink. In addition the results showed that thickness measurement numbers were different which give indicate to somehow the manufacturing process was not so perfect. Also the results of FTIR proved the degradation of the collagen in the archaeological leather document, the binding agent was Arabic gum and the leather was tanned with vegetable tanning. Isolation and identification of micro-organisms clarified the most dominant fungi isolated from the archaeological leather document were: Aspergillus niger, Aspergillus sulphureus, Aspergillus versicolor, Aspergillus sydowii, Penicillium chrysogenum, Penicillium islandicum, Alternaria alternate, Aspergillus flavus,Aspergillus terreus. Finally, the storage of the leather document was very poor which led to different aspects of deterioration. That prompted the author to suggest a new method for exhibition for the archaeological leather document. ملخص البحث باللغة العربية قطعة من الجلد الأثري محفوظة في مخزن المتحف المصري برقم JE90809 5/13677 ، تم اکتشافها عام 1966 ، وتعانى الوثيقة الجلدية مظاهر التلف المختلفة. ترکز هذه الدراسة على استخدام التقنيات التحليلية الحديثة لتحديد مکونات المخطوطة لشرح عمليات التلف. استخدمت فى الدراسة التقييم البصري ، وعملية التوثيق بواسطة کاميرا عالية الدقة والماسح الضوئي في التصوير متعدد الأطياف (MSI) ، والفحوص التشخيصية باستخدام التصوير متعدد الأطياف (VIS-UV-IR) ، وعزل وتحديد الفطريات ، والتحقيق في الشکل السطحي و نوع الحيوان باستخدام أنواع مختلفة من المجاهر: المجهر الضوئي الرقمي، المجهر الاستريو (SM) ، المجهر الاستقطابي (PM) ، ايضا تم تحديد نوع الحبر ، ومواد الدباغة بواسطة التحليل الطيفي بالأشعة تحت الحمراء (FTIR) ، وتم تحديدنوع الحبر بواسطة حيود الأشعة السينية (XRD) ، وتم قياس السمک للقطعة. بالإضافة إلى اقتراح طريقة جديدة للعرض المتحفى للوثيقة حيث أن طريقة العرض الحالية هي إلى حد ما السبب الذي تسبب في تلف القطعة. وقد أوضحت نتائج الفحوصات للعينات أن نوع الجلد المستخدم هو الأغنام مقارنة بالعينات القياسية. کما أظهرت نتائج حيود الأشعة السينية أن الحبر الأسود المستخدم هو الحبر الکربونى. بالإضافة إلى ذلک ، أظهرت النتائج اختلافا في أرقام نتائج قياس السمک للقطعة مما يدل بطريقة أو بأخرى على أن عملية التصنيع لم تکن مثالية. کما أثبتت نتائج FTIR تلف وتدهور الکولاجين في الوثيقة الجلدية ، وکان الوسيط الصمغ العربي والجلد المدبوغ تم دباغته بالتانين (الدباغة النباتية). أوضح عزل الکائنات الحية الدقيقة أن الفطريات المعزولة من هي: Aspergillus niger و Aspergillus sulphureus و Aspergillus versicolor و Aspergillus sydowii و Penicillium chrysogenum و Penicillium islandicum و Alternaria Alternus و Aspergillgillus flavus. وأخيرا ، کان تخزين المخطوطة رديئا للغاية مما أدى إلى جوانب مختلفة من التدهور. ودفع ذلک المؤلفين إلى اقتراح طريقة جديدة للعرض المتحفى للوثيقة الجلدية الأثرية.

The growth and production of hepatotoxic luteoskyrin by Penicillium islandicum

The maximal production of luteoskyrin and related pigments by Penicillium islandicum was obtained during the late phase of cultivation. Maximum growth of mycelial was observed in potato dextrose broth and the highest productivity of luteoskyrin in malt extract broth. In an optimal substrate, luteoskyrin production was the highest in the 18th day. Mycelial growth and luteoskyrin production were greater in stationary incubation than when shaken. The optimal pH for the mycelial growth was between weak acidity and neutrality. Mycelial growth and the production of luteoskyrin and related pigments were increased by supplying a carbon source such as starch, sucrose, fructose, maltose or glucose. Starch and fructose maximized mycelial growth and luteoskyrin production respectively. Lactose also enhanced luteoskyrin production but inhibited mycelial growth. The organic salts citrate,glutamate, malonate, succinate, fumarate and acetate inhibited mycelial growth and the production of luteoskyrin and related pigments. The acetate in particular displayed the strongest inhibitory effects in this test. Mycelial growth was enhanced by the following nitrogen sources: malt extract, yeast extract, peptone, casamino acid, asparagine and glutamine. However, the production of luteoskyrin and related pigments were only enhanced by malt extract, asparagine and glutamine. Potency of mycelial growth and luteoskyrin production in crops was found in the order of unpolished rice > oatmeal> wheat> polished rice> yellow corn> white corn>unhulled rice. A comparison of polished rice which had been subjected to various treatments showed boiled rice to be the best substrate for luteoskyrin production, especially in the presence of 5% sucrose.

The growth and production of hepatotoxic luteoskyrin by Penicillium islandicum

The growth and production of hepatotoxic luteoskyrin by Penicillium islandicum

Evaluation of Secondary Metabolites of Some Fungi Isolated From Beach Soils of Lagos, Nigeria Against Some Pathogens

Three beach soils in Lagos, Nigeria were screened for the presence of antibiotic producing fungi against 8 test pathogenic bacteria & fungi. The physiochemical parameters of the soils were determined following standard procedures. Soil plate dilution method was employed for isolation of marine fungi and they were identified based on cultural and microscopic characteristics. Primary screening of isolated fungi for antibiotic potential was determined by perpendicular streak method against known pathogenic test organisms (Escherichia coli, Saphylococcus aureus, Klebsiella pnuemoniae, Pseudomonas aeruginosa, Candida albicans, Saccharomyces cerevisiae,Aspergillus niger and Aspergillus fumigatus). Further sreening of the product of secondary metabolism [antibiotic] of the active fungi was done by agar disc diffusion assay. The fungus with the highest secondary activity was subjected to molecular analysis for further identification. pH of beach soils was alkaline ranging from 7.6-8.0, while temperature and moisture were normal ranging from 26.333 ± 1.155a-30.333 ± 0.577aand 7.142 ± 1.497a-10.030 ± 3.130a respectively. A total of four fungal species of 2 different genera were isolated from the beaches ;Aspergillus niger,Aspergillus flavus,Penicillium purpurogenum and Penicillium islandicum. Both primary and secondary assays revealed only antibacterial activities against Staphylococcus aureus and Psedomonas aeruginosa with no effect on all test fungi. Highest antibacterial activity[28+0.2a] was exhibited by the fungus identified as Penicillium purpurogenum. Fungi from beaches in Lagos, Nigeria may be a promising source of antibacterial agent useful in the treatment of infections caused by S. aureus and P. aeruginosa.

Biological activities of endozoic fungi isolated from Biomphalaria alexandrina snails maintained in different environmental conditions

ABSTRACT This work aims at studying Biomphalaria alexandrina snails as a source of bioactive compounds. Adult snails were maintained in plastic, mud and cement matrices. Three groups were prepared; under normal laboratory conditions, in slightly low pH conditions, and in high temperature (30°C) conditions. Nine fungal species were isolated from soft tissues of snails. Ethyl acetate and acetone extracts were prepared from each fungal species, and their biological activities were investigated. Paecilomyces variotii extracts were the most effective as antimicrobial agents, while acetone extract of Trichoderma harzianum showed high antioxidant activity. Acetone extracts of Penicillium islandicum and Aspergillus niger were highly active against hepatocellular carcinoma (HepG2) cell lines. Gas chromatography/mass spectrometry analysis of the five effective extracts showed the presence of various compounds. B. alexandrina snails may be regarded as a newly discovered source of beneficial compounds through the metabolites produced by their endozoic fungal strains.

Analysis of biochemical basis of resistance mechanism of aonla (Emblica officinalis) varieties against blue mould rot disease (Penicillium islandicum)

Experiment was carried out at Chaudhary Charan Singh Haryana Agricultural University, Hisar to understand biochemical basis of resistance under in vitro conditions in aonla (Emblica officinalis Gaertn.). In biochemical basis of resistance, it was observed that TSS (total soluble solids), total phenol, peroxidase (PO) and polyphenol oxidase activity (PPO) was higher in diseased fruits in comparison to healthy fruits. TSS and total phenol increased in healthy and diseased fruits over time interval (5 and 10 days after inoculation). The titrable acidity was significantly lower in susceptible varieties, viz. Chakaiya (healthy fruit, 1.22 % and diseased fruit, 0.98 %) and Banarasi (healthy fruit, 1.40 % and diseased fruit, 1.32 %) as compared to resistant varieties Desi (healthy fruit, 1.50 % and diseased fruit, 1.42 %) and Kanchan (healthy fruit, 1.52 % and diseased fruit, 1.51 %). Ascorbic acid in resistant varieties Desi and Kanchan was 482.03 and 500.93 mg/100 g m aonla pulp in healthy fruits while 465.59 and 476.18 mg/100 g aonla pulp in diseased fruits after 10 days of storage. PO and PPO was found to be significantly higher in diseased fruits of resistant varieties, i.e. Desi (145, 20.49 OD/min/g) and Kanchan (139, 19.50 OD min/g) as compared to diseased fruits of susceptible Chakaiya (120, 16.19 OD/min/g) and Banarasi (118, 15.14 OD/min/g) at 5 DAI. However, the activity of PO and PPO decreased after 5 days of inoculation, while acidity and ascorbic acid was low in diseased fruits when compared to healthy fruits and further decreased over time interval. Ascorbic acid and acidity was decreased over time in both healthy and diseased fruits but at faster rate in diseased fruits as compared to healthy fruits.

Effect of Temperature and Relative Humidity on Growth of Aspergillus and Penicillium spp. and Biocontrol Activity of Pseudomonas protegens AS15 against Aflatoxigenic Aspergillus flavus in Stored Rice Grains

In this study, we evaluated the effect of different temperatures (10, 20, 30, and 40 °C) and relative humidities (RHs; 12, 44, 76, and 98%) on populations of predominant grain fungi (Aspergillus candidus, Aspergillus flavus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum) and the biocontrol activity of Pseudomonas protegens AS15 against aflatoxigenic A. flavus KCCM 60330 in stored rice. Populations of all the tested fungi in inoculated rice grains were significantly enhanced by both increased temperature and RH. Multiple linear regression analysis revealed that one unit increase of temperature resulted in greater effects than that of RH on fungal populations. When rice grains were treated with P. protegens AS15 prior to inoculation with A. flavus KCCM 60330, fungal populations and aflatoxin production in the inoculated grains were significantly reduced compared with the grains untreated with strain AS15 regardless of temperature and RH (except 12% RH for fungal population). In addition, bacterial populations in grains were significantly enhanced with increasing temperature and RH, regardless of bacterial treatment. Higher bacterial populations were detected in biocontrol strain-treated grains than in untreated control grains. To our knowledge, this is the first report showing consistent biocontrol activity of P. protegens against A. flavus population and aflatoxin production in stored rice grains under various environmental conditions of temperature and RH.

Biocontrol Activity of Volatile-Producing Bacillus megaterium and Pseudomonas protegens Against Aspergillus and Penicillium spp. Predominant in Stored Rice Grains: Study II

In our previous studies, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 have been shown to be antagonistic to Aspergillus flavus in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against Aspergillus candidus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum, which are predominant in stored rice grains. In vitro and in vivo antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In in vitro tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In in vivo tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, B. megaterium KU143 and P. protegens AS15 may be potential biocontrol agents against Aspergillus and Penicillium spp. during rice grain storage.

The cyclochlorotine mycotoxin is produced by the nonribosomal peptide synthetase CctN in Talaromyces islandicus ('Penicillium islandicum').

Talaromyces islandicus ('Penicillium islandicum') is a widespread foodborne mold that produces numerous secondary metabolites, among them potent mycotoxins belonging to different chemical classes. A notable metabolite is the hepatotoxic and carcinogenic pentapeptide cyclochlorotine that contains the unusual amino acids β-phenylalanine, 2-aminobutyrate and 3,4-dichloroproline. Although the chemical structure has been known for over five decades, nothing is known about the biosynthetic pathway of cyclochlorotine. Bioinformatic analysis of the recently sequenced genome of T. islandicus identified a wealth of gene clusters potentially coding for the synthesis of secondary metabolites. Here, we show by RNA interference-mediated gene silencing that a nonribosomal peptide synthetase, CctN, is responsible for the synthesis of cyclochlorotine. Moreover, we identified novel cyclochlorotine chemical variants, whose production also depended on cctN expression. Surprisingly, the halogenase required for cyclochlorotine biosynthesis is not encoded in the cct cluster. Nonetheless, our findings enabled us to propose a detailed model for cyclochlorotine biosynthesis. In addition, comparative genomics revealed that cct-like clusters are present in all of the sequenced Talaromyces strains indicating a high prevalence of cyclochlorotine production ability.

Screening of biocatalysts for transformation of sucrose to fructooligosaccharides

• FTase production by molds, yeasts and bacteria is demonstrated. • FTase from A. flavus generated upto 63% (w/w) of FOS from sucrose. • Major fructooligosaccharides produced were GF 2 (kestose), GF 3 (nystose) and GF 4 (fructofuranosyl-nystose). Twenty microorganisms comprising of sixteen molds, two yeasts and two bacteria were evaluated for their ability to produce fructosyltransferase (FTase) and generate fructooligosaccharides (FOS) from sucrose. FTase production by these microorganisms was studied over a period of 120 h on medium containing 20% (w/v) sucrose as the sole carbon source. High FTase levels (35–31 U/ml) were observed in culture filtrates of Aspergillus flavus , Aspergillus niger , Aspergillus terreus and Penicillium islandicum . Higher concentrations of FOS were generated from 50% (w/v) sucrose using culture filtrates of A. flavus NFCCI 2364 (63.40%, w/w), A. niger SI 19 (54.94%, w/w), A. flavus NFCCI 2785 (44.61%, w/w), P. islandicum MTCC 4926 (43.56%, w/w), A. terreus NFCCI 2347 (24.17%, w/w) and Fusarium solani NFCCI 2315 (15.25%, w/w). Kestose, nystose and 1-fructofuranosyl nystose were the predominant oligosaccharides as revealed by HPLC analysis.

Mechanisms of phosphate solubilization by fungal isolates when exposed to different P sources

The use of phosphate-solubilizing fungi is a promising biotechnological strategy in the management of phosphorus (P) fertilization, as it enables the utilization of rock phosphates (RP) or the recovery of P fixed in soil particles. The objective of our study was to evaluate fungal isolates for mechanisms of solubilization of P-bearing compounds, such as AlPO4, FePO4, Ca3(PO4)2, Araxá RP, and Catalão RP. Four fungal isolates obtained from Brazilian soils were characterized in liquid media: Aspergillus niger FS1, Penicillium canescens FS23, Eupenicillium ludwigii FS27, and Penicillium islandicum FS30. A. niger FS1 was the only isolate able to solubilize all of the P sources, solubilizing 71, 36, 100, and 14 % of the P from AlPO4, FePO4, Ca3(PO4)2, and RPs, respectively. Medium acidification was an effective solubilization mechanism, particularly for Ca3(PO4)2. The other P sources were mainly solubilized through organic acids produced by the fungi. Oxalic acid, produced exclusively by A. niger FS1, and citric acid were decisive factors in the solubilization of AlPO4 and FePO4. Penicillium isolates produced more gluconic acid than A. niger FS1 in all treatments. However, this higher production did not result in higher solubilization for any of the P sources, showing that gluconic acid contributes little to the solubilization of the P sources evaluated. The higher capacity of medium acidification and the production of organic acids with stronger metal-complexation activity are characteristics that confer to A. niger FS1 a wider action on insoluble P sources. Consequently, this isolate qualifies as a promising candidate for application in the management of P fertilization.

Fungal rock phosphate solubilization using sugarcane bagasse

The effects of different doses of rock phosphate (RP), sucrose, and (NH(4))(2)SO(4) on the solubilization of RP from Araxá and Catalão (Brazil) by Aspergillus niger, Penicillium canescens, Eupenicillium ludwigii, and Penicillium islandicum were evaluated in a solid-state fermentation (SSF) system with sugarcane bagasse. The factors evaluated were combined following a 2(3) + 1 factorial design to determine their optimum concentrations. The fitted response surfaces showed that higher doses of RP promoted higher phosphorus (P) solubilization. The addition of sucrose did not have effects on P solubilization in most treatments due to the presence of soluble sugars in the bagasse. Except for A. niger, all the fungi required high (NH(4))(2)SO(4) doses to achieve the highest level of P solubilization. Inversely, addition of (NH(4))(2)SO(4) was inhibitory to P solubilization by A. niger. Among the fungi tested, A. niger stood out, showing the highest solubilization capacity and for not requiring sucrose or (NH(4))(2)SO(4) supplementation. An additional experiment with A. niger showed that the content of soluble P can be increased by adding higher RP doses in the medium. However, P yield decreases with increasing RP doses. In this experiment, the maximal P yield (approximately 60 %) was achieved with the lower RP dose (3 g L(-1)). Our results show that SSF can be used to obtain a low cost biofertilizer rich in P combining RP, sugarcane bagasse, and A. niger. Moreover, sugarcane bagasse is a suitable substrate for SSF aiming at RP solubilization, since this residue can supply the C and N necessary for the metabolism of A. niger within a range that favors RP solubilization.

Evaluation of maize cultivars for their susceptibility towards mycotoxigenic fungi under storage conditions

Maize cultivation comprises the largest area of farmland in South Africa and it is the largest food crop consumed by the majority of its population. However, this food crop is frequently associated with mycotoxin contamination. Mycotoxigenic fungi that are regularly found in South African maize were selected and evaluated against 49 commercially produced maize cultivars for their ability to infest maize during storage. Four of these fungi, known to contaminate maize in the field included Fusarium graminearum, Fusarium verticillioides, Phoma sorghina and Stenocarpella maydis. The other five species included storage fungi such as Aspergillus flavus, Aspergillus ochraceus, Eurotium repens, Penicillium islandicum and Rhizopus oryzae. A unique method of inoculation was carried out where each maize cultivar was serially inoculated with each of the fungi. Results showed that four maize cultivars had a slower rate of infestation towards the field fungi while three cultivars had a slower rate of infestation towards the storage fungi. Only one of the maize cultivars, PAN 6146, showed an overall slower infestation rate for both field and storage fungi.

Mycoflora of stored rice in relation to the biological control of Sitophilus oryzae by Anisopteromalus calandrae

In this study, we determined the effect of controlling rice weevils on the mycoflora of stored brown rice by using Anisopteromalus calandrae (Howard), a parasite of the rice weevil. The mycoflora in brown rice with the parasitoid was similar to that without the parasitoid; however, the dominant mold species differed. Without the parasitoid, Aspergillus candidus Link and Penicillium islandicum Sopp were the dominant species, whereas Aspergillus penicilloides Speg. and P. islandicum were dominant when the parasitoid was present. The difference appeared to be due mainly to the difference in the grain moisture content with and without the parasitoid. A. candidus was the dominant species in the communities without the parasitoid and was not observed when the weevils were suppressed. P. islandicum dominated or co-dominated regardless of the presence of the parasitoid which suggested that P. islandicum is tolerant to low grain moisture content or is positively affected by the presence of the rice weevil.

Isolation of Aspergillus sulphureus, Penicillium islandicum and Paecilomyces variotii from Agricultural Soil and their Biological Activity Against Pythium spinosum, the Damping-Off Organism of Soybean

Isolation of Aspergillus sulphureus, Penicillium islandicum and Paecilomyces variotii from Agricultural Soil and their Biological Activity Against Pythium spinosum, the Damping-Off Organism of Soybean

Effect of Mixed Antimicrobial Agents and Flavors in Active Packaging Films

Active packaging is an emerging food technology to improve the quality and safety of food products. Many works have been developed to study the antimicrobial activity of essential oils. Essential oils have been traditionally used as flavorings in food, so they have an important odor impact but they have as well antimicrobial properties that could be used to protect the food. Recent developments in antimicrobial active packaging showed the efficiency of essential oils versus bread and bakery products among other applications. However, one of the main problems to face is the odor and taste they could provide to the packaged food. Using some aromas to mask the odor could be a good approach. That is why the main objective of this paper is to develop an antimicrobial packaging material based on the combination of the most active compounds of essential oils (hydrocinnamaldehyde, oregano essential oil, cinnamaldehyde, thymol, and carvacrol) together with some aromas commonly used in the food industry. A study of the concentration required to get the antimicrobial properties, the organoleptic compatibility with typical aroma present in many food systems (vanilla, banana, and strawberry), and the right combination of both systems has been carried out. Antimicrobial tests of both the mentioned aromas, the main components of some essential oils, and the combination of both groups were carried out against bacteria (Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella choleraesuis, Yersinia enterocolitica, Escherichia coli), yeasts (Candida albicans, Debaryomyces hansenii, Zygosaccharomyces rouxii), and molds (Botrytis cinerae, Aspergillus flavus, Penicillium roqueforti, Eurotium repens, Penicillium islandicum, Penicillium commune, Penicillium nalgiovensis). The sensory properties of the combinations were evaluated with a triangular test and classification was by an order test; the odor threshold of the aroma compounds was also studied. The results reveal that none of the aromas had antimicrobial properties. The most antimicrobial compounds are thymol, carvacrol, and cinnamaldehyde, but none of them could be combined with banana aroma, whereas only thymol with strawberry aroma gave the right combined organoleptic profile. All of the antimicrobials under study could be combined with vanilla aroma, providing both antimicrobial property and the odor expected.