Mucor Fragilis Research Articles

Screening for the production of polyunsaturated fatty acids and cerebrosides in fungi.

To investigate fatty acid, including polyunsaturated fatty acids (PUFA), and cerebroside production of a large diversity of fungi from the Ascomycota, Basidiomycota, and Mucoromycota phyla. Seventy-nine fungal strains were grown in Kavadia medium using a microcultivation system, i.e. Duetz microtiter plates. Following cultivation, fatty acid and cerebroside contents were analyzed by gas chromatography-flame ionization detection (GC-FID) and high performance thin-layer chromatography (HPTLC), respectively. Mucoromycota fungi appeared as the most promising candidates for omega-6 PUFA production. The best omega-6 producer, including γ-linolenic acid (GLA, 18:3n-6), was Mucor fragilis UBOCC-A109196 with a concentration of 647mg L-1 total omega-6 PUFA (representing 35% of total fatty acids) and 225mg L-1 GLA (representing 12% of total fatty acids). Arachidonic acid concentration (20:4n-6) was the highest in Mortierella alpina UBOCC-A-112046, reaching 255mg L-1 and 18.56% of total fatty acids. Interestingly, several fungal strains were shown to produce omega-7 monounsaturated fatty acids. Indeed, Torulaspora delbrueckii strains accumulated palmitoleic acid (16:1n-7) up to 20% of total fatty acids, reaching 114mg L-1 in T. delbrueckii UBOCC-A-214128, while C. elegans UBOCC-A-102008 produced mainly paullinic acid (20:1n-7) with concentrations up to 100mg L-1. Concerning cerebroside production, HPTLC appeared as a relevant approach for their detection and quantification. Promising candidates belonging to the Mucoromycota phylum were found, especially in the Absidia genus with A. spinosa UBOCC-A-101332 as the best producer (12.7mg L-1). The present study highlighted PUFA and cerebroside production in a large diversity of fungi and the fact that members of the Mucoromycota phylum are good producers of PUFA as well as cerebrosides.

Effects of temperature and water activity on 25 de novo strains of pathogenic plant fungi in Al-Baha and Baljurashi cities in Saudi Arabia

Fungi inflict a great deal of damage to crops in fields and in storage facilities, causing issues such as leaf spot, wilt, rust, dieback and rot, as well as releasing mycotoxins that taint vegetation. In the current study, 25 de novo fungal isolates were taken from infected plant tissue (leaf, root and fruit), at pre- and post-harvest stages. Isolates were identified using molecular markers; 8 genera and 15 species were determined. The most common species was Penicillium spp. (40%), Aspergillus spp. (20%), Fusarium spp. (16%) and Alternaria alternata species (8%). The remaining 16% was comprised of various types of fungi, including Geotrichum candidum, Neofusicoccum parvum, Rhizopus stolonifera and Mucor fragilis. Many of these genera are known to cause significant crop damage and are notorious mycotoxin producers. An evaluation of the optimal growth temperature revealed the ideal temperatures were 30 °C for 56% of isolates, 25 °C for 28% of isolates and 20 °C for 16% of isolates. An assessment of water activity showed that 60% of isolates belonged to Penicillium and Aspergillus spp. and were mesophilic and xerophilic. Another 28% of isolates were Fusarium spp., Geotrichum candidum, Neofusicoccum parvum and Mucor fragilis, and hydrophilic. The remaining 12%, representing Alternaria alternata and Rhizopus stolonifera, were mesophilic. The current study provides accurate eco-physiological response data and molecular information for each isolate. The findings can assist the development of novel approaches to control the expansion of invasive fungal infections and minimise their deleterious consequences.

Identification and virulence screening of fungal and bacterial entomophathogens of the edible long-horned grasshopper Ruspolia differens (Orthoptera: Tettigoniidae) from Uganda

Natural enemies are major challenges in laboratory rearing of grasshoppers, but the identity and virulence of these towards the edible long-horned grasshopper Ruspolia differens (Serville) is scarcely known. In this study, fungi and bacteria were isolated from R. differens collected from Mbarara, Masaka, Hoima, Kampala and Kabale districts in Uganda in 2018, cultured on standard microbial media, identified using molecular techniques and screened for virulence against the insect in laboratory bioassays. Fourteen and nine species of fungi and bacteria were isolated from R. differens, respectively, with the number of isolates varying based on collection site. The most prevalent entomopathogenic fungal species were Aspergillus flavus Link (27.3%), Fusarium equiseti (Corda) (24.2%), Mucor fragilis Fresen (12.1%), Clonostachys rosea (Link) (6.0%) and Aspergillus tamarii Kita (6.0%); whereas the most prevalent bacterial isolates were Serratia marcescens Bizio (38.1%), Bacillus thuringiensis (Berliner) (14.3%) and Enterobacter cloacae (Jordan) (14.3%). Nine of the fungal species namely Clavispora lusitaniae Rodrigues de Miranda, Lichtheimia corymbifera (Cohn), Trichoderma koningii Oudem, F. equiseti, M. fragilis, Aspergillus niger van Tieghem, Epicoccum sorghinum (Saccardo), C. rosea, Penicillium commune Charles Thom; and five bacterial species (Proteus penneri Hickman, S. marcescens, B. thuringiensis, Staphylococcus sciuri Kloos and Enterococcus faecalis (Andrewes and Horder)) were ~5–7-fold and ~4–5-fold, more lethal to third instars of R. differens than untreated controls, respectively. This study is the first to report C. lusitaniae, Exserohilum mcginnis Padhye and Ajello, E. sorghinum, P. penneri and E. cloacae as insect pathogens. The results suggest a need to quarantine field collected R. differens before introducing them into the insectary, as well as performing antimicrobial practices during rearing of the insect to prevent entomopathogen-based mortality.

Deciphering the antifungal and plant growth-stimulating traits of the stress-tolerant Streptomyces achromogenes subsp. achromogenes strain UMAF16, a bacterium isolated from soils affected by underground fires

Crop plants are subjected to diverse abiotic and biotic stresses, which could affect their health and production. Therefore, searching for novel stress-resistant microbial agents with plant-beneficial activities is considered an urgent in agriculture. Here, we report the new stress tolerant bacterium Streptomyces achromogenes subsp. achromogenes UMAF16, isolated from a soil subjected to underground fires. Taxonomic and Genomic analysis derived from ANI (average nucleotide identity) species delimitation cut-off values, GGDC (genome-to-genome distance calculator), and phylogenetic analysis, corroborated the affiliation of UMAF16 to Streptomyces species. Genome mining of UMAF16 shows an excellent arsenal of stress tolerant genes (e.g. temperature, osmotic, and oxidative stress), as well as antifungal and plant growth-promoting mechanisms. Additionally, antiSMASH revealed multiple biosynthetic genes with antimicrobial (e.g. Achromosin, Livipeptin, Neocarazostatin A) and PGP activities (e.g. siderophores like Desferrioxamin B/Desferrioxamine E). To further confirmed previous predicted activities, it was biochemically evaluated the antifungal and plant growth-promoting mechanisms, including production of indole-3-acetic acid (IAA), proteases, siderophores, biofilm formation, and phosphate solubilization. Our results also show that strain UMAF16 grows well at temperature 50 °C, tolerates dehydration stress simulated by polyethylene glycol, and exert antifungal action against pathogens like Alternaria alternata, Mucor fragilis and Fusarium brachygibbosum. Strain UMAF16 also showed growth-stimulating activities when interacting with tomato plants, evaluated under three different plant-growth systems. Root and shoot dry weight, as well as chlorophyll content were increased in inoculated plants, compared to uninoculated controls. Finally, these results suggest a great potential of the strain UMAF16 as a bioinoculant candidate agent in stressful agriculture.

Synthesis and bioactivity evaluation of novel acetamide-derived compounds bearing a methylsulfonyl unit

This study reports the synthesis and structural characterization of a series of novel acetamide-derived compounds containing a methylsulfonyl unit. The in vitro antibacterial activity results demonstrated that compound 2-((4-fluorophenyl)sulfonyl)-N-(4-(methylsulfonyl)phenyl)acetamide (6b) exhibited superior antibacterial activities against Xanthomonas oryzae pv. oryzicolaby (Xoc), Xanthomonas oryzae pv. oryzae (Xoo), and Xanthomonas axonopodis pv. citri (Xac) at 100 μg/mL concentration, with the inhibition rates of 86.24%, 81.59%, and 75.65%, respectively, compared to Bismerthiazol and Thiodiazole copper. Meanwhile, the in vitro antifungal activities of all target compounds were found to be lower against Mucor fragilis (M. fragilis), Mucor bainieri (M. bainieri), and Trichoderma atroviride (T. atroviride) at 50 μg/mL concentration, with the inhibition rates of 0–45.21%, 0–30.24%, and 0–12.65%, respectively, compared to Carbendazim. Moreover, bioassay results of the target compounds against prostate cancer (PC3), hepatocellular carcinoma (HepG2), and leukemia (K562) cells at 10 μM concentration demonstrated that, compared to 5-fluorouracil, compound 2-((4-fluorophenyl)thio)-N-(4-(methylsulfonyl)phenyl)acetamide (4c) illustrated obvious antitumor activity (56.87%) against K562. This work first highlights the effect of the modification of the acetamide-derived compounds bearing a methylsulfonyl unit on the bioactivity evaluation.

Design, synthesis, antibacterial, and antifungal evaluation of novel 4-chromanone-derived compounds incorporating carboxamide and 1,3,4-thiadiazole thioether moieties

A series of novel botanical active component 4-chromanone derivatives incorporating carboxamide and 1,3,4-thiadiazole thioether moieties were synthesized and evaluated for their in vitro antibacterial and activities antifungal against Xanthomonas axonopodis pv. citri (Xac), Xanthomonas oryzae pv. oryzicolaby (Xoc) and Mucor bainieri (M. bainieri), Mucor fragilis (M. fragilis), Trichoderma atroviride (T. atroviride), respectively. Antibacterial screening results suggested that the target compounds showed moderate to good antibacterial activities against Xac and Xoc, to the contrary, had lower inhibitory effects on M. fragilis, M. bainieri, and T. atroviride. Among the target compounds, compound 6-chloro-N-(5-(methylthio)-1,3,4-thiadiazol-2-yl)-4-oxochromane-2-carboxamide (6f) had the best inhibition rates against Xac (85.15% and 72.41%, respectivelty) and Xoc (95.14% and 82.09%) at 200 and 100 μg/mL, which were superior to Bismerthiazol and Thiodiazole copper. As far as we know, it is the first report on the design, synthesis, and bioactivity evaluation of novel 4-chromanone-derived compounds incorporating carboxamide and 1,3,4-thiadiazole thioether moieties.

Pre- and Post-Harvest Infection of Pasteurized Pickles with Fungi and Their Pectinolytic Potential to Soften the Product

Fungi and their enzymes have long been thought to cause the softening of pasteurized gherkins; however, the exact fungal species and timing of contamination are unknown. Ready-to-sell pickle jars and blossoms of growing gherkins were inoculated with DNA-sequenced fungi isolated from rotting gherkins to cause softening at various stages of production. Ready-to-sell gherkins inoculated with Fusarium oxysporum, Fusarium equiseti, Galactomyces geotrichum, Mucor circinelloides, Mucor hiemalis, Mucor fragilis, Plectosphaerella cucumerina, Alternaria sp., and Cladosporium sp. indicated a measurable texture reduction after pasteurization and 6 months of storage at room temperature. No texture changes were observed in gherkins infected during the growth phase. The fungi M. hiemalis, M. fragilis, and G. geotrichum tolerated the acidic-saline (approx. pH 4) environment in the jar for several days, thus the pectinolytic enzymes of these candidates were tested for heat and pH resistance. Although the measured endo-Polygalacturonase (PG) of M. fragilis had its optimum activity at pH < 4, all fungal enzymes were inactivated within 3 min at 80 °C corresponding to the pasteurization heat. Our study shows that conventionally occurring fungi and their enzymes have the potential to induce softening in pickles. Softening by these fungi is unlikely due to post- or pre-harvest contamination without any other influences.

Novel botanical active component derivatives containing carboxamide and 1,3,4-Thiadiazole thioether moieties: Design, synthesis, and inhibitory activity.

In this study, using the botanical active components of carvacrol, thymol, guaiacol, and sesamol as the lead structures, 19 novel botanical active component derivatives containing carboxamide and 1,3,4-thiadiazole thioether moieties (5a−5s) were synthesized and structurally characterized by 1H NMR, 13C NMR, and HRMS. The antibacterial bioassay results in vitro showed that compound 2-(2-methoxyphenoxy)-N-(5-(methylthio)-1,3,4-thiadiazol-2-yl)acetamide (5k) revealed excellent inhibitory activities against Xanthomonas axonopodis pv. citri (Xac) and Xanthomonas oryzae pv. oryzicolaby (Xoc), with the median effective concentration (EC50) values of 22 and 15 μg/ml, respectively, which were even better than those of thiodiazole copper and bismerthiazol. Meanwhile, all the target compounds revealed lower in vitro inhibitory effects on Mucor bainieri (M. bainieri), Mucor fragilis (M. fragilis), and Trichoderma atroviride (T. atroviride), than carbendazim.

Diversity of Endophytic and Pathogenic Fungi of Saffron (Crocus sativus) Plants from Cultivation Sites in Italy

Crocus sativus is an important crop for the production of saffron and bioactive compounds. Plant endophytic fungi are a source of secondary metabolites additional to those produced by the plant itself. We analysed the biodiversity of endophytic fungi present in corms, stems, leaves, tepals, and stigmas of C. sativus from ten Italian sites; furthermore, we isolated putative pathogenic fungi from rotten plants. We used an in vitro isolation approach followed by molecular analysis of the internal transcribed spacer (ITS rDNA) region. We obtained 165 strains belonging to 39 OTUs, spreading over 26 genera and 29 species. Dark septate endophytes of the genus Cadophora and the species Talaromyces pinophilus dominated in corms, while Alternaria alternata, Epicoccum spp., T. pinophilus, Mucor fragilis, and Stemphylium vesicarium dominated in other tissues. The most frequently isolated pathogens were Fusarium oxysporum and Rhizopus oryzae. Endophytic communities significantly differed among tissues and life stages, whereas differences among cultivation sites were not statistically supported. Several endophytes were hypothesized to have changing trophic modes and/or to be latent pathogens in C. sativus. All strains were conserved ex-situ for future bioactivity tests and production of metabolites.

Primary and secondary metabolites produced in Salvia miltiorrhiza hairy roots by an endophytic fungal elicitor from Mucor fragilis

Salvia miltiorrhiza is one of the most commonly used medicinal materials in China. In recent years, the quality of S. miltiorrhiza has attracted much attention. Biotic and abiotic elicitors are widely used in cultivation to improve the quality of medicinal plants. We isolated an endophytic fungus, Mucor fragilis, from S. miltiorrhiza. We compared the effects of endophytic fungal elicitors with those of yeast extract together with silver ion, widely used together as effective elicitors, on S. miltiorrhiza hairy roots. Seventeen primary metabolites (amino acids and fatty acids) and five secondary metabolites (diterpenoids and phenolic acids) were analyzed after elicitor treatment. The mycelium extract promoted the accumulation of salvianolic acid B, rosmarinic acid, stearic acid, and oleic acid in S. miltiorrhiza hairy roots. Additionally, qPCR revealed that elicitors affect the accumulation of primary and secondary metabolites by regulating the expression of key genes (SmAACT, SmGGPPS, and SmPAL). This is the first detection of both the primary and secondary metabolites of S. miltiorrhiza hairy roots, and the results of this work should help guide the quality control of S. miltiorrhiza. In addition, the findings confirm that Mucor fragilis functions as an effective endophytic fungal elicitor with excellent application prospect for cultivation of medicinal plants.

First Report of Mucor spp. Causing Root Rot of Radix pseudstellariae in Guizhou Province of China.

Radix pseudostellariae L. is one of the most common and highly-prized Chinese medicinal plants with various pharmacological effects, and mainly produced in acid soils in the Guizhou and Fujian provinces of southwestern and southeastern China, respectively (Wu et al. 2020). However, consecutive monoculture of R. pseudostellariae results in severe root rot and decline in biomass and quality of underground tubers. Root tubers of R. pseudostellariae are typically planted in December and harvested in next June. Root rot commonly starts developing in May. The disease incidence of root rot was ranging from 37 to 46% in root portions and basal stem of R. pseudostellariae under the consecutive monoculture fields in Shibing County, Guizhou Province, China (108°12'E, 27°03'N) (Li et al. 2017). Severe root rot was observed in Shibing County in May 2018. Infected plants displayed curly, withered, and yellow leaves, blight, retarded growth, root rot, and yield losses. Abundant whitish mycelia were observed on roots and surrounding soil. Two fungal isolates, designated GZ20190123 and GZ20190124, were obtained from symptomatic roots cultured on potato dextrose agar (PDA). The optimum temperature range for growth of the two isolates was 25 to 30°C. The optimum pH range for the growth of GZ20190123 was 5 to 5.5, whereas GZ20190124 grew better between pH 5 to 8.5. The mean mycelial growth rates of GZ20190123 and GZ20190124 at 30°C were 2.1 and 1.5 cm/day, respectively. Conidia of the two isolates were ovoid or obclavate and were produced in single or branched chains. The internal transcribed spacer (ITS) region was amplified with primers ITS1 and ITS4 (White et al. 1990). The sequences were deposited in GenBank as accession No. MN726736 for GZ20190123 and MN726738 for GZ20190124. Sequence comparison revealed 99% (GZ20190123) and 97% (GZ20190124) identity with previously reported isolate xsd08071 of Mucor racemosus Bull. (accession No. FJ582639.1) and isolate BM3 of Mucor fragilis Bainier (accession No. MK910058.1), respectively, which was confirmed by phylogenetic analysis. The two isolates were tested for pathogenicity on R. pseudostellariae. Six roots of R. pseudostellariae were surface-sterilized with 75% ethanol and stab inoculated with mycelia using a sterile toothpick for each isolate. Sterile distilled water was stab inoculated to twelve roots to serve as the control. Treated roots were incubated in a greenhouse with 16 h day length [light intensity 146.5 μmol/(m2·s)] and day/night temperature 26°C/18°C. The inoculated roots showed the expected symptoms on roots and sprouts 7 days after inoculation, whereas the control roots with sprouts did not show any symptom. The fungi were re-isolated from the diseased roots and confirmed as expected M. racemosus or M. fragilis based on the ITS sequences, which satisfied Koch's postulates. Thus, isolate GZ20190123 was identified as M. racemosus and GZ20190124 as M. fragilis. Previously, M. racemosus and M. fragilis have been reported as a pathogen on tomato (Kwon and Hong 2005) and grape (Ghuffar et al. 2018), respectively. To our knowledge, this is the first report of M. racemosus and M. fragilis causing root rot of R. pseudostellariae in southwestern China, where the disease could cause a significant loss to production of this important medicinal plant.

Five novel and highly efficient endophytic fungi isolated from Huperzia serrata expressing huperzine A for the treatment of Alzheimer’s disease

Huperzine A (Hup A) is an important drug for treating Alzheimer's disease (AD) and mainly extracted from the Huperzia serrata (Thunb.) Trevis. (Lycopodiaceae) (HS). Nevertheless, the content of Hup A in HS is very low of 0.007% with growing circle of 8 to 10 years, and the chemical synthesis of Hup A still has some insurmountable limitations in the industrialized production. So, the available resources of Hup A for clinical treatment of AD are scarce. The purpose of this work was to construct a biosynthesis platform based on the endophytic fungi from HS. In this work, five endophytic fungi Mucor racemosus NSH-D, Mucor fragilis NSY-1, Fusarium verticillioides NSH-5, Fusarium oxysporum NSG-1, and Trichoderma harzianum NSW-V were firstly found and isolated from the Chinese folk medicine HS, which were identified according to their morphological characteristics and nuclear ribosomal DNA ITS sequences. The highest efficient fungus could effectively biosynthesize Hup A in a liquid culture of 319.8 ± 0.17 mg/L which were 112 times higher than that of other reported conventional endophytic fungi. Moreover, these fungi with higher hereditary stability could possess the initial expressing ability of Hup A after 40 generations, and the expressed Hup A from these biosynthesis systems has prior physicochemical properties, a better inhibition activity of acetylcholinesterase and a lower cytotoxicity compared with the listed active pharmaceutical ingredients (APIs) of Hup A. These results provide promising alternative resources for producing Hup A at an industrial scale by biosynthesis, and it may also shed light on millions of AD patients. KEY POINTS: • Five novel endophytic fungi with high stability could highly express prior Hup A Graphical abstract.

First Report of Mucor fragilis Causing Bunch Rot of Grapes in Punjab, Pakistan

First Report of <i>Mucor fragilis</i> Causing Bunch Rot of Grapes in Punjab, Pakistan

Cultural, morphological, pathogenic and molecular characterization of Mucor fragilis causing bunch rot of grapes in Pakistan and its bio management through plant essential oil

Cultural, morphological, pathogenic and molecular characterization of Mucor fragilis causing bunch rot of grapes in Pakistan and its bio management through plant essential oil

High-throughput screening of Mucoromycota fungi for production of low- and high-value lipids

BackgroundMucoromycota fungi are important producers of low- and high-value lipids. Mortierella alpina is used for arachidonic acid production at industrial scale. In addition, oleaginous Mucoromycota fungi are promising candidates for biodiesel production. A critical step in the development of such biotechnological applications is the selection of suitable strains for lipid production. The aim of the present study was to use the Duetz-microtiter plate system combined with Fourier transform infrared (FTIR) spectroscopy for high-throughput screening of the potential of 100 Mucoromycota strains to produce low- and high-value lipids.ResultsWith this reproducible, high-throughput method, we found several promising strains for high-value omega-6 polyunsaturated fatty acid (PUFA) and biodiesel production purposes. Gamma-linolenic acid content was the highest in Mucor fragilis UBOCC-A-109196 (24.5% of total fatty acids), and Cunninghamella echinulata VKM F-470 (24.0%). For the first time, we observed concomitant gamma-linolenic acid and alpha-linolenic acid (up to 13.0%) production in psychrophilic Mucor flavus strains. Arachidonic acid was present the highest amount in M. alpina ATCC 32222 (41.1% of total fatty acids). Low cultivation temperature (15 °C) activated the temperature sensitive ∆17 desaturase enzyme in Mortierella spp., resulting in eicosapentaenoic acid production with up to 11.0% of total fatty acids in M. humilis VKM F-1494. Cunninghamella blakesleeana CCM-705, Umbelopsis vinacea CCM F-539 and UBOCC-A-101347 showed very good growth (23–26 g/L) and lipid production (7.0–8.3 g/L) with high palmitic and oleic acid, and low PUFA content, which makes them attractive candidates for biodiesel production. Absidia glauca CCM 451 had the highest total lipid content (47.2% of biomass) of all tested strains. We also demonstrated the potential of FTIR spectroscopy for high-throughput screening of total lipid content of oleaginous fungi.ConclusionsThe use of Duetz-microtiter plate system combined with FTIR spectroscopy and multivariate analysis, is a feasible approach for high-throughput screening of lipid production in Mucoromycota fungi. Several promising strains have been identified by this method for the production of high-value PUFA and biodiesel.

Occurrence and diversity of fungal pathogens associated with water hyacinth and their potential as biocontrol agents in the Rift Valley of Ethiopia

ABSTRACTWater hyacinth poses serious socio-economic and environmental problems in Ethiopia. To integrate fungal pathogens into water hyacinth management, a survey was conducted in the Rift Valley of Ethiopia. Based on morphological characterization and DNA sequencing, 25 fungal species were identified that belong to nine genera. Alternaria tenuissima, A. alternata, Aspergillus niger, Phoma sp., Curvularia trifolii, Mucor fragilis, M. racemosus, A. fumigatus, Fusarium oxysporum, and F. equiseti were the most common fungi detected. However, their occurrence was influenced by water wave action, temperature, season, and altitude. Among the fungal pathogens, A. alternata, A. tenuissima, F. oxysporum, F. equiseti, and Neofisicoccum parvum were highly pathogenic to water hyacinth. Alternaria alternata and A. tenuissima did not cause disease symptoms on ecologically important plant species (e.g. Noug, Tef, and Coffee). Application of the fungal pathogens on water hyacinth plants also showed 11%–67%, 22%–72%, 15%–55%, and 12%–50% reduction in fresh weight, dry weight, plant height, and root length of water hyacinth, respectively. This study suggests that fungal species have the potential to control water hyacinth biologically and provides baseline data for biological control efforts in the future.

Characterization of Two New Records of Mucoralean Species Isolated from Gut of Soldier Fly Larva in Korea

While surveying the diversity of fungi of the order Mucorales, two isolates, EML-PUKI12-1 and EML-PUKI06-1, were obtained from the gut of soldier fly larvae inhabiting the bulrush at a pond located in the Chonnam National University Arboretum, Gwangju, Korea. The isolates were confirmed as Mucor irregularis and Mucor fragilis species, respectively, based on the morphological characteristics and phylogenetic analysis of rDNA internal transcribed spacer region. Such mucoralean species belonging to undiscovered taxa has not previously been described in Korea.

Novel fungal lipids for the production of biodiesel resources by Mucor fragilis AFT7‐4

A newly isolated oleaginous fungus strain Mucor fragilis AFT7‐4 screened from farmland soil was shown to be a prospective producer of microbial lipid. To improve oil production, lipid collection techniques involving cell disruption and oil extraction were investigated, and fermentation conditions were also optimized by response surface methodology with a 3‐level 4‐factor Box‐Behnken Design. The results showed that the method, which is the combination of acid‐heating and freeze‐thawing worked best for cell disruption, and chloroform/methanol solution (2:1, v/v) was the most suitable extraction system for oils extraction. Under the optimum conditions [glucose concentration 86 g/L, ammonium sulfate concentration 2.5 g/L, inoculum concentration (v/v) 11%, fermentation time 5 days], a lipid yield of 12.86 g/L and the lipid content of 46.80% could be achieved. These represented a 33.63% improvement in the lipid yield and a 44.44% increase in the lipid content compared with the original values (9.04 g/L and 32.41%). This work was firstly studied on a Mucor fragilis strain systematically for oil production. © 2016 American Institute of Chemical Engineers Environ Prog, 2016 © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1784–1792, 2016

Identification of mucorales from clinical specimens: a 4-year experience in a single institution.

Mucormycosis, a fatal opportunistic infection in immunocompromised hosts, is caused by fungi belonging to the order Mucorales. Early diagnosis based on exact identification and multidisciplinary treatments is critical. However, identification of Mucorales fungi is difficult and often delayed, resulting in poor prognosis. This study aimed to compare the results of phenotypic and molecular identification of 12 Mucorales isolates collected from 4-yr-accumulated data. All isolates were identified on the basis of phenotypic characteristics such as growth rate, colony morphology, and reproductive structures. PCR and direct sequencing were performed to target internal transcribed spacer (ITS) and/or D1/D2 regions. Target DNA sequencing identified five Lichtheimia isolates, two Rhizopus microsporus isolates, two Rhizomucor pusillus isolates, one Cunninghamella bertholletiae isolate, one Mucor fragilis isolate, and one Syncephalastrum racemosum isolate. Five of the 12 (41.7%) isolates were incorrectly identified on the basis of phenotypic identification. DNA sequencing showed that of these five isolates, two were Lichtheimia isolates, one was Mucor isolate, one was Rhizomucor isolate, and one was Rhizopus microspores. All the isolates were identified at the species level by ITS and/or D1/D2 analyses. Phenotypic differentiation and identification of Mucorales is difficult because different Mucorales share similar morphology. Our results indicate that the molecular methods employed in this study are valuable for identifying Mucorales.

Assessment of microbial contamination within working environments of different types of composting plants

The objective of the study was to determine the degree of microbiological contamination, type of microflora, bioaerosol particle size distribution, and concentration of endotoxins in dust in different types of composting plants. In addition, this study provides a list of indicator microorganisms that pose a biological threat in composting facilities, based on their prevalence within the workplace, source of isolation, and health hazards. We undertook microbiological analysis of the air, work surfaces, and compost, and assessed the particle size distribution of bioaerosols using a six-stage Andersen sampler. Endotoxins were determined using gas chromatography–mass spectrometry (GC-MS). Microbial identification was undertaken both microscopically and using biochemical tests. The predominant bacterial and fungal species were identified using 16S rRNA and ITS1/2 analysis, respectively. The number of mesophilic microorganisms in composting plants amounted to 6.9 × 102–2.5 × 104 CFU/m3 in the air, 2.9 × 102–3.3 × 103 CFU/100 cm2 on surfaces, and 2.2 × 105–2.4 × 107 CFU/g in compost. Qualitative analysis revealed 75 microbial strains in composting plants, with filamentous fungi being the largest group of microorganisms, accounting for as many as 38 isolates. The total amount of endotoxins was 0.0062–0.0140 nmol/mg of dust. The dust fraction with aerodynamic particle diameter of 0.65–1.1 μm accounted for 28–39% of bacterial aerosols and 4–13% of fungal aerosols. We propose the following strains as indicators of harmful biological agent contamination: Bacillus cereus, Aspergillus fumigatus, Cladosporium cladosporioides, C. herbarum, Mucor hiemalis, and Rhizopus oryzae for both types of composting plants, and Bacillus pumilus, Mucor fragilis, Penicillium svalbardense, and P. crustosum for green waste composting plants. The biological hazards posed within these plants are due to the presence of potentially pathogenic microorganisms and the inhalation of respirable bioaerosol. Depending on the type of microorganism, these hazards may be aggravated or reduced after cleaning procedures.Implications: This study assessed the microbial contamination in two categories of composting plants: (1) facilities producing substrates for industrial cultivation of button mushrooms, and (2) facilities for processing biodegradable waste. Both workplaces showed potentially pathogenic microorganisms, respirable bioaerosol, and endotoxin. These results are useful to determine the procedures to control harmful biological agents, and to disinfect workplaces in composting plants.