Production and characterization of extracellular liamocins produced from fungal strains of Aureobasidium spp.

Liamocins, a group of high-density glycolipids, are only produced by certain strains of the yeast-like fungi in the genus Aureobasidium. Until now, few studies have focused on the surfactant properties of liamocins produced from the highly diverse tropical strains of Aureobasidium. Therefore, the aims of this research were to screen the liamocin production from tropical strains of Aureobasidium spp. and to characterize their surfactant properties. A total of 41 strains of Thai Aureobasidium spp. were screened for their ability to produce liamocins, and the products were detected using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thin-layer chromatography. Of those strains, 30 strains of Aureobasidium spp. tested were found to produce liamocins with yields ranging from 0.53 to 10.60 g/l. The nature of all crude liamocins was heterogeneous, with different compositions and ratios depending on the yeast strain. These liamocins exhibited relatively high emulsifying activity against vegetable oils tested, with an emulsification index of around 40-50%; the emulsion stability of some liamocins was up to 30 days. The obtained critical micelle concentration values were varied, with those ​​of liamocins produced from A. pullulans, A. melanogenum and A. thailandense falling in ranges from 7.70 to 119.78, 10.73 to > 1,000, and 68.56 to > 1,000 mg/l, respectively. The emulsification activity of liamocins was higher than that of the analytical grade rhamnolipids. These compounds showed strong surface tension reduction in a sodium chloride concentration range of 2-12% (w/v), pH values between 3 and 7, and temperatures between 4 and 121 °C. This is the first report of liamocins produced by A. thailandense.

Effect of Surfactant Concentrations on Physicochemical Properties and Functionality of Curcumin Nanoemulsions Under Conditions Relevant to Commercial Utilization.

Surfactants are used to stabilize nanoemulsions by protecting their physical stability and preventing deterioration of the entrapped bioactive during processing and storage. The effect of surfactant concentration on physical-chemical properties of nanoemulsions with entrapped curcumin, relevant to commercial applications, was addressed in this research. Furthermore, the functionality of nanoemulsified curcumin in terms of lipid oxidation inhibition was determined. Protection against varying pH and thermal treatments was more significant in the nanoemulsions at the elevated surfactant level, but at these high concentrations, the surface charges of the emulsions dramatically decreased under sodium salt addition, which may result in instability over time. Nanoemulsions showed the potential to inhibit malondialdehyde (MDA) formulation by protecting the entrapped curcumin and enhance its antioxidant activity when added to milk. The fortified milk with added curcumin systems had a yellow color compared to the control. The results of the study are critical in choosing the surfactant concentration needed to stabilize emulsified curcumin, and to protect the entrapped curcumin under specific conditions of use to support the utilization of curcumin nanoemulsions as a food additive in different commercial products.

Computational and in vitro analyses of the antibacterial effect of the ethanolic extract of Pluchea indica L. leaves.

The most common gram-negative, Escherichia coli, and gram-positive bacteria, Bacillus spp., have evolved different mechanisms that have caused the emergence of multi-drug resistance. As a result, drugs that block the bacterial growth cycle are needed. Here, in silico and in vitro studies were performed to assess compounds in the Pluchea indica leaf extract, a medicinal plant, that can inhibit bacterial proteins. Briefly, P. indica leaves were extracted using ethanol. The crude extract was then subjected to gas chromatography-mass spectrometry for metabolite screening. Molecular docking simulations with rhomboid protease (Rpro) (Protein data bank ID number: 3ZMI from E. coli and filamenting temperature-sensitive mutant Z (FtsZ) protein data bank ID number: 2VAM from Bacillus subtilis were performed. Moreover, the well diffusion method was used to confirm the antibacterial activity of P. indica leaf extract. A total of 10 compounds were identified in the P. indica extract and used for computational analysis. Based on drug-likeness prediction, P. indica compounds may be drug-like molecules. Binding affinity tests indicated that 10,10-Dimethyl-2,6-dimethylenebicyclo(7.2.0)undecan-5.ß.-ol and 11,11-Dimethyl-4,8-dimethylenebicyclo(7.2.0)undecan-3-ol had the most negative values. Accordingly, these compounds may be potential ligands that bind to bacterial proteins. The root mean square fluctuation values was <2 Å, indicating stable fluctuation binding for the ligand-protein complex. According to in vitro antibacterial assays, a high concentration (50%) of the P. indica extract markedly inhibited E. coli and B. subtilis, with inhibitory zone diameters of 31.86±1.63 and 21.09±0.09 mm, respectively. Overall, the compounds in the P. indica leaf extract were identified as functional inhibitors of E. coli and B. subtilis proteins via in silico analysis. This may facilitate development of antibacterial agents.

The antioxidant and antimicrobial activity of ethanolic extract in roots, stems, and leaves of three commercial Cymbopogon species.

BACKGROUND: Cymbopogon is a member of the family Poaceae and has been explored for its phytochemicals and bioactivities. Although the antimicrobial activities of Cymbopogon spp. extracts have been extensively studied, comprehensive analyses are required to identify promising compounds for the treatment of antimicrobial resistance. Therefore, this study investigated the antioxidant and antimicrobial properties of Cymbopogon spp. ethanolic extracts in every single organ. METHODS: Ethanolic extracts were obtained from three Indonesian commercial species of Cymbopogon spp., namely Cymbopogon citratus (L.) Rendle, Cymbopogon nardus (DC.) Spatf., and Cymbopogon winterianus Jowitt. The leaf, stem, and root extracts were evaluated via metabolite profiling using gas chromatography-mass spectrometry (GC-MS). In silico and in vitro analyses were used to evaluate the antioxidant and antimicrobial properties of the Cymbopogon spp. ethanolic extracts. In addition, bioactivity was measured using cytotoxicity assays. Antioxidant assays were performed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis [3-ethylbenzothiazoline-6-sulfonic acid (ABTS) to determine toxicity to Huh7it-1 cells using a tetrazolium bromide (MTT) assay. Finally, the antimicrobial activity of these extracts was evaluated against Candida albicans, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli using a well diffusion assay. RESULTS: GC-MS analysis revealed 53 metabolites. Of these, 2,5-bis(1,1-dimethylethyl)- phenol (27.87%), alpha-cadinol (26.76%), and 1,2-dimethoxy-4-(1-propenyl)-benzene (20.56%) were the predominant compounds. C. winterianus and C. nardus leaves exhibited the highest antioxidant activity against DPPH and ABTS, respectively. Contrastingly, the MTT assay showed low cytotoxicity. C. nardus leaf extract exhibited the highest antimicrobial activity against E. coli and S. aureus, whereas C. winterianus stem extract showed the highest activity against B. substilis. Furthermore, computational pathway analysis predicted that antimicrobial activity mechanisms were related to antioxidant activity. CONCLUSIONS: These findings demonstrate that the leaves had strong antioxidant activity, whereas both the leaves and stems showed great antimicrobial activity. Furthermore, all Cymbopogon spp. ethanolic extracts showed low toxicity. These findings provide a foundation for future studies that assess the clinical safety of Cymbopogon spp. as novel drug candidates.

Antimicrobial potentials of Pandanus amaryllifolius Roxb.: Phytochemical profiling, antioxidant, and molecular docking studies.

The emergence of antimicrobial resistance has led to an urgent need for novel antimicrobial drugs. This study aimed to determine the antioxidant and antimicrobial potentials in silico and in vitro of Pandanus amaryllifolius Roxb. ethanolic extract. The extracts were subjected to gas chromatography-mass spectrometry (GC-MS) analysis to identify the compounds. In silico antimicrobial studies were performed to gain insights into the possible mechanism of action of the active compounds as antimicrobials. The antimicrobial activities of the ethanolic extracts were assessed using the agar well diffusion method against the Surabaya strain of Escherichia coli and Staphylococcus aureus. Antioxidant properties of the extract were done using DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and ABTS [2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid)] inhibition assays. The phytochemical screening revealed that the extract has high flavonoids and polyphenols contents. The GC-MS analysis detected the presence of 52 bioactive substances, with n-hexadecanoic acid, 9, 12, 15-octadecatrienoic acid, benzofuran 2,3-dihydro-. quinic acid, neophytadiene as major compound. Molecular docking studies showed that these compounds have a high binding affinity towards the target proteins, thereby inhibiting their activities. The ethanolic extract of P. amaryllifolius Roxb. exhibited antioxidant and antimicrobial activities. The IC50 were 11.96 ± 4.01 µg/ml and 26.18 ± 7.44 µg/ml for DPPH and ABTS. The diameters of inhibition zones (DIZ) and percentage of inhibition (PI) were calculated and varied for every single pathogen 16.44 ± 1.21mm/66.76 ± 4.92% (50%) and 21.22 ± 0.11mm/82.49 ± 3.91% (50%) for E. coli and S. aureus (DIZ/PI) respectively. Overall, this study provides information on the mechanism responsible for P. amaryllifolius Roxb. extract as a natural antimicrobe and lays the foundation for further studies to isolate and characterize the active compounds as antimicrobial candidates.

Effects of sugar and amino acid supplementation on Aureobasidium pullulans NRRL 58536 antifungal activity against four Aspergillus species.

Cultured cell extracts from ten tropical strains of Aureobasidium pullulans were screened for antifungal activity against four pathogenic Aspergillus species (Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus, and Aspergillus terreus) using the well diffusion and conidial germination inhibition assays. The crude cell extract from A. pullulans NRRL 58536 resulted in the greatest fungicidal activity against all four Aspergillus species and so was selected for further investigation into enhancing the production of antifungal activity through optimization of the culture medium, carbon source (sucrose and glucose) and amino acid (phenylalanine, proline, and leucine) supplementation. Sucrose did not support the production of any detectable antifungal activity, while glucose did with the greatest antifungal activity against all four Aspergillus species being produced in cells grown in medium containing 2.5 % (w/v) glucose. With respect to the amino acid supplements, variable trends between the different Aspergillus species and amino acid combinations were observed, with the greatest antifungal activities being obtained when grown with phenylalanine plus leucine supplementation for activity against A. flavus, proline plus leucine for A. terreus, and phenylalanine plus proline and leucine for A. niger and A. fumigatus. Thin layer chromatography, spectrophotometry, high-performance liquid chromatography, (1)H-nuclear magnetic resonance, and MALDI-TOF mass spectrometry analyses were all consistent with the main component of the A. pullulans NRRL 58536 extracts being aureobasidins.

In vitro antioxidant and anticancer activities of Smilax corbularia extract combined with Phellinus linteus extract against breast cancer cell lines.

Treatment with extracts from whole herbs has been reported to synergistically enhance the anticancer activities of therapeutic agents in recent studies. The present study evaluated the antioxidant and anticancer activities of Smilax corbularia Kunth (S. corbularia) and Phellinus linteus (P. linteus) crude extracts individually and in combination. S. corbularia was extracted using ethanol, whereas P. linteus was extracted using hot water. Both crude extracts underwent physiochemical characterization. Subsequently, the possible antioxidant activities of both crude extracts, individually and in combination, were evaluated using 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assays. Their effects on breast cancer cell cytotoxicity, proliferation and apoptosis were then assessed. The crude S. corbularia extract obtained was found to have a high level of total phenolic content, whilst the crude P. linteus extract had high levels of total polysaccharide content. The total phenolic content and total polysaccharide content results of the combinations depended on the respective ratios of the individual extracts. S. corbularia alone and combination 3 (which contained 75% S. corbularia: 25% P. linteus) demonstrated the greatest radical scavenging activity, followed by combination 1 (50% S. corbularia: 50% P. linteus), combination 2 (25% S. corbularia: 75% P. linteus) and P. linteus. The toxicity results of the extract samples on the cancer cells corresponded with their antioxidant activity. In particular, certain combinations demonstrated clearer inhibitory effects on cell proliferation against three types of breast cancer cells compared with those exerted by the two individual extracts. However, induction of apoptosis was limited, with the degree of apoptosis observed to be #x003C;5%. These findings suggested that treatment with combinations of these two extracts could confer enhanced antioxidant and antiproliferative effects on breast cancer cells. Therefore, the potential of these two extracts in combination as anticancer agents warrants further investigation.

Antiproliferative activity and apoptosis­inducing effects of Trametes polyzona polysaccharides against human breast cancer cells.

Fungal polysaccharides have garnered interest due to their biological activities in terms of anticancer properties and antioxidant activity. The present study aimed to evaluate the anticancer properties and antioxidant activity of a newly isolated white-rot fungus, Trametes polyzona CU07 from Thailand. Crude T. polyzona polysaccharides (CTPPs) were extracted from mycelia using hot water. The chemical properties, including total carbohydrates, molecular weight and protein content, and Fourier-transform infrared spectroscopy analysis, were then investigated. The antioxidant activity was determined against the radicals 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anticancer properties were evaluated in MCF-7 breast cancer (BC) cells, whereas the 293 cell line was used as a control. The inhibitory effects of CTPPs on viability were determined by MTT assay, followed by BrdU incorporation assay to assess cell proliferation. The induction of apoptosis was determined by flow cytometry. CTPPs were considered polysaccharide-protein conjugates, which had molecular weights in the range of 0.3-22,528 kDa. They contained ~50 and 37% carbohydrate and protein, respectively, with glucose as the main monosaccharide component. Notably, CTPPs had high antioxidant activity against ABTS, and had a significant inhibitory effect on the MCF-7 cell line with a half-maximal inhibitory concentration value of 0.58 mg/ml. However, they exhibited little effect on the 293 cell line. The BrdU incorporation assay demonstrated that CTPPs inhibited proliferation by ~20% compared with that in untreated cells. CTPPs also induced early- and late-stage apoptosis of MCF-7 cells. These results indicated that the CTPPs may exhibit potential antiproliferative and antioxidant activity, and apoptosis-inducing effects against human BC cells.

In silico anti-SARS-CoV-2, antiplasmodial, antioxidant, and antimicrobial activities of crude extracts and homopterocarpin from heartwood of Pterocarpus macrocarpus Kurz.

Natural products play an essential role in new drug discovery. In the present study, we determined the anti-SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus-2), antioxidant, antiplasmodial, and antimicrobial activities of Pterocarpus macrocarpus Kurz. heartwood and structurally characterized the bioactive compounds. P. macrocarpus Kurz. heartwood was macerated with n-hexane, ethyl acetate, and ethanol, respectively, for 7 days, three times. The compounds were isolated by recrystallization with n-hexane and evaluated by thin-layer chromatography (TLC), gas chromatography-mass spectrophotometry (GC-MS), Fourier transform infrared spectroscopy (FITR), and nuclear magnetic resonance (NMR) spectroscopy. Ethyl acetate, ethanol, n-hexane extracts, and homopterocarpin exhibited antiplasmodial activity at 1.78, 2.21, 7.11, and 0.52 µg/ml, respectively, against P. falciparum 3D7 with low toxicity (selectivity index/SI ≥ 28.46). GC-MS identified compound showed in silico anti-SARS-CoV-2 binding affinity with stigmasterol and SARS-CoV-2 helicase of -8.2 kcal/mol. Ethyl acetate extract exhibited the best antioxidant activity against DPPH (0.76 ± 0.92 µg/ml) and ABTS (0.61 ± 0.46 µg/ml). They also demonstrated antimicrobial activity against B. subtilis, ethanol and ethyl acetate extracts against E. coli and C. albicans, and ethanol extract against S. aureus with diameter zone of inhibition of more than 1 cm. The results highlighted antiplasmodial activity of extracts and homopterocarpin from P. macrocarpus Kurz. heartwood and its potent binding in silico to anti-SARS-CoV-2 proteins with low toxicity. This study also confirmed that extracts exhibited antioxidant and antimicrobial activities. Further studies are needed to assess the safety and clinical trial of P. macrocarpus Kurz. for development as new drug candidate.

Xylooligosaccharides produced from sugarcane leaf arabinoxylan using xylanase from Aureobasidium pullulans NRRL 58523 and its prebiotic activity toward Lactobacillus spp.

In an attempt to enhance the value of sugarcane leaf, xylan was extracted and used for xylooligosaccharide (XO) production via enzymatic hydrolysis using xylanase from the black yeast Aureobasidium pullulans. The xylan was extracted from sugarcane leaf using alkali extraction according to the response surface methodology. The highest xylan yield (99.42 ± 4.05 % recovery) was obtained using 14.32 % (w/v) NaOH, 13.25:1 liquid: solid ratio, at 121 °C and 15 lb.in2 for 32 min. Sugar composition and FTIR spectrum analyses confirmed its structure as arabinoxylan. The extracted arabinoxylan had a relatively high molecular weight compared to previous studies. Crude endoxylanase from A. pullulans NRRL 58523 was selected for enzymatic hydrolysis of the xylan. The enzyme hydrolyzed well at 50 °C, pH 4.0 and was relatively stable under this condition (87.38 ± 1.26 % of the activity remained after 60 h). XOs, especially xylobiose and xylotriose, were obtained at the maximum yield of 237.51 ± 17.69 mg/g xylan via endoxylanase hydrolysis under the optimum conditions (50 °C, pH 4.0, 65.31 U/g xylan, 53 h). XOs exhibited species-specific prebiotic activity toward three strains of Lactobacillus spp. but not toward Bifidobacterium spp.

In vitro and in vivo antiplasmodial activities of leaf extracts from Sonchus arvensis L.

BACKGROUND: Malaria continues to be a global problem due to the limited efficacy of current drugs and the natural products are a potential source for discovering new antimalarial agents. Therefore, the aims of this study were to investigate phytochemical properties, cytotoxic effect, antioxidant, and antiplasmodial activities of Sonchus arvensis L. leaf extracts both in vitro and in vivo. METHODS: The extracts from S. arvensis L. leaf were prepared by successive maceration with n-hexane, ethyl acetate, and ethanol, and then subjected to quantitative phytochemical analysis using standard methods. The antimalarial activities of crude extracts were tested in vitro against Plasmodium falciparum 3D7 strain while the Peter's 4-day suppressive test model with P. berghei-infected mice was used to evaluate the in vivo antiplasmodial, hepatoprotective, nephroprotective, and immunomodulatory activities. The cytotoxic tests were also carried out using human hepatic cell lines in [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay. RESULT: The n-hexane, ethyl acetate, and ethanolic extracts of S. arvensis L. leaf exhibited good in vitro antiplasmodial activity with IC50 values 5.119 ± 3.27, 2.916 ± 2.34, and 8.026 ± 1.23 µg/mL, respectively. Each of the extracts also exhibited high antioxidant with low cytotoxic effects. Furthermore, the ethyl acetate extract showed in vivo antiplasmodial activity with ED50 = 46.31 ± 9.36 mg/kg body weight, as well as hepatoprotective, nephroprotective, and immunomodulatory activities in mice infected with P. berghei. CONCLUSION: This study highlights the antiplasmodial activities of S. arvensis L. leaf ethyl acetate extract against P. falciparum and P. berghei as well as the antioxidant, nephroprotective, hepatoprotective, and immunomodulatory activities with low toxicity. These results indicate the potential of Sonchus arvensis L. to be developed into a new antimalarial drug candidate. However, the compounds and transmission-blocking strategies for malaria control of S. arvensis L. extracts are essential for further study.

Production and characterization of thermostable acidophilic ß-mannanase from Aureobasidium pullulans NRRL 58524 and its potential in mannooligosaccharide production from spent coffee ground galactomannan.

The maximum yield of the crude mannanase from Aureobasidium pullulans NRRL 58524 was 8.42 ± 0.18 U mL-1 when cultured for 72 h in the optimized medium containing 3% (w v-1) defatted spent coffee grounds (SCG) and 0.67% (w v-1) ammonium sulphate. Two forms of mannanase were observed in the crude enzyme and the principal mannanase was enriched to apparent homogeneity via sequential filtration and anion exchange chromatography. The molecular mass of the enzyme was approximately 63 kDa as determined by SDS-PAGE. The enriched mannanase was active at high temperatures (45-75 °C) and a pH range from 3 to 6 with the maximum activity at 55 °C and pH 4.0. The enzyme was relatively thermostable with more than 75% of its initial activity remained after a 12 h incubation at 55 °C. The half-lives of the enriched mannanase were over 8 and 6 h at 60 and 65 °C, respectively. The enzyme was not adversely affected by chelator and most ions tested. This enzyme could hydrolyze both glucomannan and galactomannan and exhibited limited catalytic activity on beta-glucan. When the crude mannanase was used to hydrolyze galactomannan extracted from SCG, the maximum yield of reducing sugars mainly comprising of mannobiose (16.27 ± 0.84 mg 100 mg-1), and mannotriose (2.85 ± 0.20 mg 100 mg-1) was obtained at 58.22 ± 2.04 mg 100 mg-1 dry weight, under optimized condition (84.87 U g-1 mannanase, 41 h 34 min incubation at 55 °C and pH 4.0). These results suggested the prospect of the enzyme in mannan hydrolysis and mannooligosaccharide production at a larger scale. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03301-4.

α-Amylase activity during pullulan production and α-amylase gene analyses of Aureobasidium pullulans.

Aureobasidium pullulans is the source of commercially produced pullulan, a high molecular weight polysaccharide that is used in the manufacture of edible films. It has been proposed that α-amylase decreases the molecular weight of pullulan in late cultures. Based on a recent phylogenetic analysis, five representative strains were chosen to study the relationship between α-amylase and pullulan production. In sucrose-grown cultures, pullulan yields increased over time while the molecular weight of pullulan generally decreased. However, no α-amylase activity was detected in these cultures. Low levels of α-amylase were present in starch-grown culture, but pullulan analysis was complicated by residual starch. To facilitate further studies on the role of α-amylase in the reduction of pullulan molecular weight, the α-amylase gene from A. pullulans NRRL Y-12974 was cloned and characterized. The coding region of the complete α-amylase gene contains 2,247 bp, including 7 introns and 8 exons. The putative mRNA was 1,878 bp long, encoding an α-amylase of 625 amino acid residues. Southern blot analysis indicated that there was only one copy of this gene in the genome. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that the gene was transcribed in both sucrose- and starch-grown cultures. It is possible that very low levels of α-amylase attack the minor maltotetraose subunits of pullulan and cause the reduction of molecular weight.

Growth, secondary metabolite production, and in vitro antiplasmodial activity of Sonchus arvensis L. callus under dolomite [CaMg(CO3)2] treatment.

Malaria is still a global health problem. Plasmodium is a single-cell protozoan parasite that causes malaria and is transmitted to humans through the female Anopheles mosquito. The previous study showed that Sonchus arvensis L. callus has antiplasmodial activity. Several treatments are needed for callus quality improvement for antimalarial compound production. This study aimed to examine the effect of dolomite [CaMg(CO3)2] on growth (morpho-anatomical structure and biomass), secondary metabolite production, and in vitro antiplasmodial activity of S. arvensis L. callus. In this study, leaf explants were grown in Murashige and Skoog medium with a combination of 2,4-dichlorophenoxyacetic acid (2,4-D, one mg/L) and 6-benzyl amino purine (BAP, 0.5 mg/L) with dolomite (50, 75, 100, 150, and 200 mg/L). The 21 days callus ethanolic and methanolic extract were analyzed by gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). The antiplasmodial test was performed on a blood culture infected with Plasmodium falciparum strain 3D7 using the Rieckmann method. The results showed that dolomite significantly affected callus growth, metabolite profile, and in vitro antiplasmodial activity. Dolomite (150 mg/L) showed the highest biomass (0.590 ± 0.136 g fresh weight and 0.074 ± 0.008 g dry weight). GC-MS analysis detected four compounds from callus ethanolic extract. Pelargonic acid, decanoic acid, and hexadecanoic acid were major compounds. One new terpenoid compound is based on TLC analysis. S. arvensis L. callus has antiplasmodial activity with the IC50 value of 5.037 µg/mL. It was three times lower than leaf methanolic extract and five times lower than leaf ethanolic extract.

Toxicity evaluation and biodegradation of phenanthrene by laccase from Trametes polyzona PBURU 12.

The newly isolated Trametes polyzona PBURU 12 demonstrated a high tolerance and potential for the degradation of phenanthrene. The fungal isolate was able to tolerate 100 ppm of phenanthrene with 45% relative growth. The crude laccase produced by Trametes polyzona PBURU 12 was able to degrade phenanthrene by up to 98% within 24 h. The degradation metabolites showed the absence of toxic compounds. Microbial viability tests using E. coli and B. subtilis revealed that the treated phenanthrene was less toxic than untreated phenanthrene. Phytotoxicity and genotoxicity tests, using Vigna radiata and Allium cepa, indicated that the treated phenanthrene was less toxic to the plants. No mutagenic activity was found in the Ames test. The crude laccase from Trametes polyzona PBURU 12 was demonstrated as a potential tool for the biodegradation of PAHs (phenanthrene), with low toxic effects after the degradation.

Antioxidant and UV-Blocking Properties of a Carboxymethyl Cellulose-Lignin Composite Film Produced from Oil Palm Empty Fruit Bunch.

Oil palm empty fruit bunch (EFB) pulp with the highest cellulose content of 83.42% was obtained from an optimized process of acid pretreatment (0.5% v/v H2SO4), alkaline extraction (15% w/w NaOH), and hydrogen peroxide bleaching (10% w/v H2O2), respectively. The EFB cellulose was carboxymethylated, and the obtained carboxymethyl cellulose (CMC) was readily water-soluble (81.32%). The EFB CMC was blended with glycerol and cast into a composite film. Lignin that precipitated from the EFB black liquor was also incorporated into the film at different concentrations, and its effect on the UV-blocking properties of the film was determined. Interestingly, the EFB CMC film without lignin addition completely blocked UV-B transmittance. The incorporation of lignin at all concentrations significantly enhanced the UV-A blocking and other physical properties of the film, including the surface roughness, thickness, and thermal stability, although the tensile strength and water vapor permeability were not significantly affected. Complete UV-A and UV-B blocking were observed when lignin was added at 0.2% (w/v), and the film also exhibited the highest antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals with an half-maximal inhibitory concentration (IC50) value of 3.87 mg mL-1.

Multilocus phylogenetic analyses, pullulan production and xylanase activity of tropical isolates of Aureobasidium pullulans.

Aureobasidium pullulans is the source of the commercially valuable polysaccharide pullulan and the enzyme xylanase. Isolates are typically off-white to pale pink or black on solid media, while some tropical isolates have been described as 'color variants' with bright pigments of red, yellow or purple. We sequenced 5 loci (internal transcribed spacer, intergenic spacer 1, translation elongation factor-1 alpha, beta tubulin, and RNA polymerase II) from 45 new isolates from Thailand. Based on the phylogenetic analyses, isolates were classified into 12 clades. Each clade showed different colors on different culture media including two clades with 'color variants' and some clades exhibited high levels of pullulan production or xylanase activity. Colony characteristics do not correlate perfectly with DNA sequence phylogeny or the physiological characters, but DNA sequence differences rapidly identify isolates with genetic novelty.

Fusigen Reduces Intracellular Reactive Oxygen Species and Nitric Oxide Levels.

BACKGROUND/AIM: Oxidative stress caused by the production of excessive cellular reactive oxygen species (ROS) and high levels of nitric oxide contribute to several human pathologies. This study aimed to examine the anti-oxidant effects of fusigen, a compound produced from Aureobasidium melanogenum. MATERIALS AND METHODS: Extracts of A. melanogenum were selected as a source for the isolation of fusigen. The anti-oxidant, nitric oxide suppression, as well as the free radical scavenging activities of fusigen were tested in BEAS-2B human bronchial epithelial cell line (BEAS-2B cells) and human dermal papilla cells (DP cells) using specific fluorescence dyes and flow cytometry analysis. Cell viability was determined by the MTT assay. RESULTS: Fusigen did not exert cytotoxicity in the human normal BEAS-2B and DP cells at concentrations up to 100 µM. Fusigen decreased basal levels of cellular ROS, as well as the levels of ROS induced by hydrogen peroxide and ferrous ion enrichment. ROS decreasing effect was confirmed in DP cells. In addition, fusigen treatment suppressed intracellular NO levels in both BEAS-2B and DP cells. CONCLUSION: The optimal process of production of purified fusigen from A. melanogenum was determined. Fusigen exhibited a low cytotoxic effect and the potential to suppress ROS and NO. These results demonstrated that fusigen may be used for the treatment or prevention of human diseases.

Production of cutinase from Fusarium falciforme and its application for hydrophilicity improvement of polyethylene terephthalate fabric.

Among 23 isolates of cutinase-producing fungi from Thailand, one strain of Fusarium falciforme PBURU-T5 exhibited the greatest cutinase activity (3.36 ± 0.12 U ml-1) against p-nitrophenyl butyrate. This strain was found to produce an inducible cutinase when cultivated in the liquid mineral medium containing cutin from papaya peel as the sole carbon source. By optimizing the production condition based on the central composite experimental design, the maximal cutinase activity up to 4.82 ± 0.18 U ml-1 was attained under the condition: 0.4% (w/v) papaya cutin as the carbon source, 0.3% (w/v) peptone as the nitrogen source, incubation temperature at 30 °C for 4 days, and initial pH 7.0. The crude enzyme was optimally active at 35 °C and pH 9.0 which was suitable for textile industrial application. The treatment with the crude PBURU-T5 cutinase (100 U g-1 dry weight of fabric) could enhance the wetting time, water adsorption and moisture regain of polyethylene terephthalate fabric up to 1.9-, 1.2- and 1.3-fold, respectively, comparing with the conventional 1M NaOH treatment. The increment of these fabric properties by enzymatic treatment could facilitate the dyeing process and enhance the fabric softness. Thus, F. falciforme PBURU-T5 is the promising source of cutinase for the modification of the PET fabric surface.

Enzymatic hydrolysis of tropical weed xylans using xylanase from Aureobasidium melanogenum PBUAP46 for xylooligosaccharide production.

The maximum yield of xylanase from Aureobasidium melanogenum PBUAP46 was 5.19 ± 0.08 U ml-1 when cultured in a production medium containing 3.89% (w/v) rice straw and 0.75% (w/v) NaNO3 as carbon and nitrogen sources, respectively, for 72 h. This enzyme catalyzed well and was relatively stable at pH 7.0 and room temperature (28 ± 2 °C). The produced xylanase was used to hydrolyze xylans from four tropical weeds, whereupon it was found that the highest amounts of reducing sugars in the xylan hydrolysates of cogon grass (Imperata cylindrical), Napier grass (Pennisetum purpureum), and vetiver grass (Vetiveria zizanioides) were at 20.44 ± 0.84, 17.50 ± 0.29, and 19.44 ± 0.40 mg 100 mg xylan-1, respectively, but it was not detectable in water hyacinth (Eichhornia crassipes) hydrolysate. The highest combined amount of xylobiose and xylotriose was obtained from vetiver grass; thus, it was selected for further optimization. After optimization, xylanase digestion of vetiver grass xylan at 27.94 U g xylan-1 for 92 h 19 min gave the highest amount of reducing sugars (23.65 ± 1.34 mg 100 mg xylan-1), which were principally xylobiose and xylotriose. The enriched XOs exhibited a prebiotic property, significantly stimulating the growth of Lactobacillus brevis and L. casei by a factor of up to 3.5- and 6.5-fold, respectively, compared to glucose.