•Sugarcane bagasse as raw material for production of sustainable compounds.•Sophorolipid production by T. mucoides using hemicellulosic hydrolysate.•Highly stable biosurfactant under severe ...temperature, pH and salinity conditions.•Biosurfactant as an alternative product for lignocellulosic biorefineries.
In this study, sugarcane bagasse hemicellulosic hydrolisate was evaluated as carbon source in biosurfactant production by yeasts. 27 yeasts were screened in culture media based on commercial xylose, non-detoxified and detoxified sugarcane bagasse hydrolysate to select potential strains for BS production with emulsifying and tensoactive properties. Cutaneotrichosporon mucoides UFMG-CM-Y6148 cultured in medium based on detoxified hydrolysate was the best producer of biosurfactant with a volumetric productivity of 0.167 g.L−1. h−1 and highlighted emulsifying properties in kerose as emulsification index higher than 50% and an emulsifying activity of 1.0 EU. mL−1, and its effectiveness was demonstrated over a wide range of temperature, pH and salt concentration. The chromatography and spectrometry analysis demonstrated that the BS produced by C. mucoides UFMG-CM-Y6148 was a sophorolipid. The results obtained in this study demonstrated the successful sustainable prodution of biosurfactant by yeasts in media with hemicellulosic hydrolysate and the viability of these products for biorefineries.
Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single ...cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as “weeds” in the ant-fungus symbiosis.
Aim
To screen and identify a potential biosurfactant‐producing yeast strain isolated from Antarctic soil and to evaluate the fermentation process kinetics of the most promising strain on ...biosurfactant production using glycerol as carbon source.
Methods and Results
From the 68 isolated yeast strains, 11 strains were able to produce biosurfactants after Emulsification Index (E.I.) and Drop Collapse tests, reaching an E.I. higher than 10%. Strain 1_4.0 was the best producer, identified as Candida glaebosa based on molecular analysis. Yeast was cultivated in a medium composed of glycerol supplemented with yeast extract for 120 h to determine the process kinetics. The increased C/N ratio affected yeast growth and biosurfactant production. Biosurfactant release was associated with the end of exponential and beginning of the stationary growth phases. Results indicated an E.I. of 30% at the end of the fermentation.
Conclusions
The feasiability of C. glaebosa to produce biosurfactant from a low‐cost medium cultivation shows a great impact on the development of bioresource in the Antarctica terrestrial environment.
Significance and Impact of the Study
Although the diversity of psychrophilic/psychrotolerant micro‐organisms from Antarctica has been the preferred subject of study by microbiologists, terrestrial microfungal communities are scarcely investigated and literature about the biotechnological potential of such micro‐organisms should cover important biomolecules in addition to cold‐adapted enzymes. In the present study, for the first time, the Maritime Antarctica environment was screened as a novel source of biosurfactants produced by micro‐organisms.
The aim of the present study was to investigate the taxonomic identity of yeasts isolated from the Antarctic continent and to evaluate their ability to produce enzymes (lipase, protease and xylanase) ...at low and moderate temperatures. A total of 97 yeast strains were recovered from marine and terrestrial samples collected in the Antarctica. The highest amount of yeast strains was obtained from marine sediments, followed by lichens, ornithogenic soils, sea stars,
Salpa
sp., algae, sea urchin, sea squirt, stone with lichens,
Nacella concinna
, sea sponge, sea isopod and sea snail. Data from polyphasic taxonomy revealed the presence of 21 yeast species, distributed in the phylum Ascomycota (
n
= 8) and Basidiomycota (
n
= 13). Representatives of encapsulated yeasts, belonging to genera
Rhodotorula
and
Cryptococcus
were recovered from 7 different Antarctic samples. Moreover,
Candida glaebosa
,
Cryptococcus victoriae
,
Meyerozyma (Pichia) guilliermondii
,
Rhodotorula mucilaginosa
and
R. laryngis
were the most abundant yeast species recovered. This is the first report of the occurrence of some species of yeasts recovered from Antarctic marine invertebrates. Additionally, results from enzymes production at low/moderate temperatures revealed that the Antarctic environment contains metabolically diverse cultivable yeasts, which could be considered as a target for biotechnological applications. Among the evaluated yeasts in the present study 46.39, 37.11 and 14.43 % were able to produce lipase (at 15 °C), xylanase (at 15 °C) and protease (at 25 °C), respectively. The majority of lipolytic, proteolytic and xylanolytic strains were distributed in the phylum Basidiomycota and were mainly recovered from sea stars, lichens, sea urchin and marine sediments.
Riding with the ants Duarte, A P M; Attili-Angelis, D; Baron, N C ...
Persoonia,
06/2017, Volume:
38, Issue:
1
Journal Article
Peer reviewed
Open access
Isolates of Teratosphaeriaceae have frequently been found in the integument of attine ants, proving to be common and diverse in this microenvironment. The LSU phylogeny of the ant-isolated strains ...studied revealed that they cluster in two main lineages. The first was associated
with the genus Xenopenidiella whereas the other represented two ant-isolated lineages sister to the taxa Penidiella aggregata and P. drakensbergensis, which are allocated to the new genus Penidiellomyces. The genus Penidiella is limited to the lineage containing
P. columbiana, which is not congeneric with Penidiellomyces or Penidiellopsis, nor with Simplicidiella, a novel genus introduced here to accommodate a strain isolated from ants. For species level analysis, the final 26 aligned sequences of the ITS (498 characters),
cmdA (389 characters), tef1 (342 characters) and tub2 (446 characters) gene regions lead to the introduction of six new species in Xenopenidiella, and one in respectively Penidiellopsis and Simplicidiella. The species described in this study were
distinguished by the combination of morphological and phylogenetic data. Novelties on the integument of leaf-cutting ants from Brazil include: Penidiellopsis ramosus, Xenopenidiella clavata, X. formica, X. inflata, X. laevigata, X. nigrescens,
X. tarda spp. nov., and Simplicidiella nigra gen. & sp. nov. Beta-tubulin is recommended as primary barcode for the distinction of species in Penidiellopsis, whereas ITS was sufficient to distinguish species of Xenopenidiella.
Fungus-growing ants of the genus Atta are known for their leaf-cutting habit, a lifestyle they have maintained since their 50-million-year-old co-evolution with a mutualistic fungus, cultivated as ...food. Recent studies have highlighted that, in addition to the mutualistic fungus, nests of ants harbor a great diversity of microbial communities. Such microorganisms include the dematiaceous fungi, which are characterized by their melanized cell walls. In order to contribute to the knowledge of fungal ecology, as well as opportunistic strains that may be dispersed by these social insects, we isolated and identified fungi carried by gynes of Atta capiguara and Atta laevigata, collected from colonies located in Fazenda Santana, Botucatu (São Paulo, Brazil). The isolation was carried out using the oil flotation technique, which is suitable for the growth of black fungi. Inoculated plates were incubated at 25 and 35 °C until black cultures were visible (20–45 days). Isolates were identified based on microscopic and molecular characteristics. Some isolated genera were: Cladophialophora, Cladosporium, Exophiala, Ochroconis, Phaeococcomyces, Phialophora and Penidiella. Hyaline species were also found. The results obtained from this work showed that leaf-cutting gynes may contribute to the dispersal of opportunistic dematiaceous fungi. It is suggested that more attention should be paid to this still unexplored subject.
Ochroconis globalis, a novel species of the melanized genus Ochroconis (Sympoventuriaceae, Venturiales), is described and illustrated and distinguished phenotypically and molecularly from existing ...ochroconis-like species. Phylogenetic analyses using nuclear ribosomal DNA genes (nuSSU, ITS, nuLSU) and coding gene fragments (ACT1, BT2, TEF1) revealed clustering of all strains as a monophyletic clade which was well separated from known Ochroconis species. Most strains of the new species were obtained from human-made environments, while the natural habitat of the species remains enigmatic. The new combination Ochroconis musae is introduced for one of the most commonly encountered Ochroconis species, and a phenotypic key to all species is provided.
Nine strains of a novel yeast species were isolated from rotting wood, tree bark, ant nests or living as endophytes in leaves of Vellozia gigantea. Analysis of the sequences of the internal ...transcribed spacer (ITS) region and the D1/D2 domains of the large subunit rRNA gene showed that this species was related to Candida insectorum in the Yamadazyma clade. The novel species differed from closely related species by 10 and 11 substitutions in the ITS region and the D1/D2 domains of the large subunit of the rRNA gene, respectively. The species is heterothallic and forms asci with one to two hat-shaped ascospores. The name Yamadazyma riverae sp. nov. is proposed for the novel species. The type strain is UFMG-CM-Y444T ( = CBS 14121T) and the allotype strain is TT12 ( = CBS 14098 = UFMG-CM-Y577). The Mycobank number is MB 813221.
Thirty-nine yeast strains were recovered from a field nest of a primitive and putative novel attine ant species in the genus Myrmicocrypta (Hymenoptera: Formicidae: tribe Attini). Yeasts isolated ...from the fungus garden and waste deposit included Candida dubliniensis, Candida oleophila, Cryptococcus haglerorum and Hanseniaspora uvarum. In addition, one morphological type was isolated overwhelmingly. Sequencing data of partial large-subunit (LSU) rDNA and the internal transcribed spacer (ITS) region coupled with morphological and physiological characterization accommodated this morphotype in a separate taxonomic position in relation to the known species of Trichosporon (Basidiomycota: Trichosporonales). Here, we propose a novel yeast species named Trichosporon chiarellii sp. nov. based on the description of 34 isolates; the type strain is strain FCP 540806(T) (=CBS 11177(T)).
Ants in the tribe Attini (Hymenoptera, Formicidae) maintain a 50 million-year-old lifestyle of co-evolution with symbiotic basidiomycetous fungi which they cultivate as essential source of nutrition. ...However, other microorganisms have been reported from ant habitats indicating a higher diversity of consistently associated species than established to date. Recently, black yeast-like fungi have been reported as a possible symbiont, like a competitor of the actinomycete bacteria that grow in the integument of the insects. During the mating season, gynes of
Atta capiguara
and
A. laevigata
were collected from nests located in Botucatu, SP, Brazil and sampled using flotation technique. Phylogenetic analysis based on ITS, partial 28S (LSU) and β-tubulin sequences revealed the occurrence of two novel species of
Phialophora
among the melanized fungi isolated.
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