Use of waste frying oil and coconut pulp for the production, isolation, and characterization of a new lipase from Moesziomyces aphidis.

Lipases comprise the third most commercialized group of enzymes worldwide and those of microbial origin are sought for their multiple advantages. Agro-industrial waste can be an alternative culture medium for producing lipases, reducing production costs and the improper disposal of waste frying oil (WFO). This study aimed to produce yeast lipases through submerged fermentation (SF) using domestic edible oil waste as inducer and alternative culture medium. The optimal culture conditions, most effective inducer, and purification method for a new lipase from Moesziomyces aphidis BRT57 were identified. Yeast was cultured in medium containing green coconut pulp and WFO waste for 72 h. The maximum production of lipases in SF occurred in a culture medium containing WFO and yeast extract at 48 and 72 h of incubation, with enzyme activities of 8.88 and 11.39 U mL-1, respectively. The lipase was isolated through ultrafiltration followed by size exclusion chromatography, achieving a 50.46 % recovery rate. To the best of our knowledge, this is the first study to report the production and purification of lipases from M. aphidis, demonstrating the value of frying oil as inducer and alternative medium for SF, contributing to the production of fatty acids for biodiesel from food waste.

Yeasts from tropical forests: Biodiversity, ecological interactions, and as sources of bioinnovation.

Tropical rainforests and related biomes are found in Asia, Australia, Africa, Central and South America, Mexico, and many Pacific Islands. These biomes encompass less than 20% of Earth's terrestrial area, may contain about 50% of the planet's biodiversity, and are endangered regions vulnerable to deforestation. Tropical rainforests have a great diversity of substrates that can be colonized by yeasts. These unicellular fungi contribute to the recycling of organic matter, may serve as a food source for other organisms, or have ecological interactions that benefit or harm plants, animals, and other fungi. In this review, we summarize the most important studies of yeast biodiversity carried out in these biomes, as well as new data, and discuss the ecology of yeast genera frequently isolated from tropical forests and the potential of these microorganisms as a source of bioinnovation. We show that tropical forest biomes represent a tremendous source of new yeast species. Although many studies, most using culture-dependent methods, have already been carried out in Central America, South America, and Asia, the tropical forest biomes of Africa and Australasia remain an underexplored source of novel yeasts. We hope that this review will encourage new researchers to study yeasts in unexplored tropical forest habitats.

Different plant compartments, different yeasts: The example of the bromeliad phyllosphere.

The plant phyllosphere is one of the largest sources of microorganisms, including yeasts. In bromeliads, the knowledge of yeasts is dispersed and still incipient. To understand the extent of our knowledge of the subject, this review proposes to compile and synthesize existing knowledge, elucidating possible patterns, biotechnological and taxonomic potentials, bringing to light new knowledge, and identifying information gaps. For such, we systematically review scientific production on yeasts in bromeliads using various databases. The results indicated that the plant compartments flowers, fruits, leaves, and water tank (phytotelma) have been studied when focusing on the yeast community in the bromeliad phyllosphere. More than 180 species of yeasts and yeast-like fungi were recorded from the phyllosphere, 70% were exclusively found in one of these four compartments and only 2% were shared among all. In addition, most of the community had a low frequency of occurrence, and approximately half of the species had a single record. Variables such as bromeliad subfamilies and functional types, as well as plant compartments, were statistically significant, though inconclusive and with low explanatory power. At least 50 yeast species with some biotechnological potentials have been isolated from bromeliads. More than 90% of these species were able to produce extracellular enzymes. In addition, other biotechnological applications have also been recorded. Moreover, new species have been described, though yeasts were only exploited in approximately 1% of the existing bromeliads species, which highlights that there is still much to be explored. Nevertheless, it appears that we are still far from recovering the completeness of the diversity of yeasts in this host. Furthermore, bromeliads proved to be a good ecological model for prospecting new yeasts and for studies on the interaction between plants and yeasts. In addition, the yeast community diverged among plant compartments, establishing bromeliads as a microbiologically complex and heterogeneous mosaic.

Tremella ananatis sp. nov. and Tremella lamprococci sp. nov., two yeast species associated with bromeliads.

Eight yeast isolates with an affinity to the genus Tremella were obtained from bromeliads from different locations in Brazil. Although the formation of basidia and basidiocarp were not observed, on the basis of the results of sequence analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene and internal transcribed spacer (ITS) region, we suggest that these isolates represent two novel species of the genus Tremella. These yeasts are phylogenetically related to Tremella saccharicola and Tremella globispora. Therefore, we propose Tremella ananatis sp. nov. and Tremella lamprococci sp. nov. as novel yeast species of the order Tremellales (Agaricomycotina, Basidiomycota). Sequence analysis revealed that Tremella ananatis sp. nov. differs by 11 and 28 nucleotide substitutions from Tremella saccharicola in the D1/D2 sequence and ITS region, respectively. Moreover, Tremella lamprococci sp. nov. differs by 15 and 29 nucleotide substitutions from Tremella globispora in the D1/D2 sequence and ITS region, respectively. The holotypes of Tremella ananatis sp. nov. and Tremella lamprococci sp. nov. are CBS 14568T and CBS 14567T, and the MycoBank numbers are MB840480 and MB840481, respectively.

Anti-Trichomonas vaginalis activity and chemical analysis of metabolites produced by marine-associated fungi.

Trichomoniasis is the most common non-viral sexually transmitted infection worldwide and it may have serious consequences, especially for women. Currently, 5-nitroimidazole drugs are the treatment of choice for trichomoniasis, although presenting adverse effects and reported cases of drug resistance. Metabolites isolated from marine fungi have attracted considerable attention due to their unique chemical structures with diverse biological activities, including antiprotozoal activity. In this study, we showed the anti-Trichomonas vaginalis activity of fractions obtained from marine fungi and the chemical composition of the most active fraction was determined. Ethyl acetate fractions of the fungus Aspergillus niger (EAE03) and Trichoderma harzianum/Hypocrea lixii complex (EAE09) were active against T. vaginalis. These samples, EAE03 and EAE09, were also effective against the fresh clinical isolate metronidazole-resistant TV-LACM2R, presenting MIC values of 2.0 mg/mL and 1.0 mg/mL, respectively. The same MIC values were found against ATCC 30,236 T. vaginalis isolate. In vitro cytotoxicity revealed only the fraction named EAE03 with no cytotoxic effect; however, the active fractions did not promote a significant hemolytic effect after 1-h incubation. Already, the in vivo toxicity evaluation using Galleria mellonella larvae demonstrated that none of the tested samples caused a reduction in animal survival. The fraction EAE03 was followed for purification steps and analyzed by LC-DAD-MS. Eleven compounds were annotated, including butyrolactone, butanolide, and atromentin. Overall, the range of activities reported confirms the potential of marine fungi to produce bioactive molecules.

Wickerhamiella martinezcruziae f. a., sp. nov., a yeast species isolated from tropical habitats.

Four yeast isolates with an affinity to the genus Wickerhamiella were obtained from beach sand, a marine zoanthid and a tree exudate at different localities in Brazil. Two other isolates with almost identical ITS and D1/D2 sequences of the large subunit rRNA gene were isolated from the small intestine of cattle and a grease trap in Thailand. These isolates represent a novel species phylogenetically related to Wickerhamiella verensis, Wickerhamiella osmotolerans, Wickerhamiella tropicalis, Wickerhamiella sorbophila and Wickerhamiella infanticola. The novel species differs by 15-30 nucleotide differences from these species in the D1/D2 sequences. The name Wickerhamiella martinezcruziae f.a., sp. nov. is proposed. The holotype of Wickerhamiella martinezcruziae sp. nov. is CBS 16104T. The MycoBank number is MB 839328.

Polyketides from marine-derived Aspergillus welwitschiae inhibit Staphylococcus aureus virulence factors and potentiate vancomycin antibacterial activity in vivo.

Staphylococcus aureus, a major cause of nosocomial and community associated infections, is becoming increasingly resistant to antibiotics. S. aureus infections are frequently biofilm-associated, and a diverse spectrum of virulence factors are determinant in the pathogenicity, which can be an interesting target resulting in less selective pressure for bacterial resistance. This study reports anti-virulence activity against S. aureus, including a MRSA clinical isolate, of naphto-γ-pyrones from Aspergillus welwitschiae mycelium, and the characterization of chemical constituents by LC-DAD and LC-MS. A remarkable decrease in biofilm formation, hemolysis and coagulation promoted by Staphylococcus aureus, important traits for bacterial pathogenicity, were observed. Furthermore, advantageous association with vancomycin resulted in significant protection against staphylococcal infection in Galleria mellonella model. These findings corroborate the importance of natural products as a source of new therapeutic possibilities, as well reveals potential alternatives for infection control using anti-virulence and drug association approaches.

Vishniacozyma alagoana sp. nov. a tremellomycetes yeast associated with plants from dry and rainfall tropical forests.

Plants are important reservoirs of described and undescribed species of yeast. During a study of yeasts associated with bromeliads from the Northeast region of Brazil (collected in 2013-2017), analysis of the D1/D2 domain of the LSU rRNA and internal transcribed spacer (ITS) region identified eleven strains of yeasts as representing an unknown species of the genus Vishniacozyma. The species may have a diverse habitat in Brazil as a strain was collected from a flowering plant (Acanthaceae) in 1994. As a consequence, we propose Vishniacozyma alagoana sp. nov. as a member of the tremellomycetes yeasts (Agaricomycotina, Basidiomycota). Vishniacozyma alagoana sp. nov. was found in Atlantic Forest (a tropical rainforest) and the Caatinga (a seasonally dry tropical forest) associated with bromeliads in northeast and southeastern Brazil. The proposed novel species is related to Vishniacozyma taibaiensis and distinguished by eight nucleotide substitutions in the D1/D2 domain and seventeen in the ITS region. In addition, Vishniacozyma alagoana sp. nov. differs from V. taibaiensis by the ability to assimilate ribitol. The holotype is CBS 15966T.

Diversity of filamentous fungi associated with coral and sponges in coastal reefs of northeast Brazil.

Fungi are known to form associations with various marine organisms and substrata such as sponges and corals, both as potential symbionts or pathogens. These microorganisms occupy an ecological niche that has recently attracted great attention due to their potential in either ecological or pharmaceutical advances. However, the interaction between marine invertebrates and fungi is still poorly understood, including how they are affected by anthropogenic actions. Here, we identified 89 fungal isolates through sequencing of the ITS rDNA region obtained from the various sponge and coral species collected at two northeast Brazilian reefs. We found 43 species of fungi from 16 genera, all belonging to phylum Ascomycota. The sponges and coral shared four genera: Aspergillus, Penicillium, Trichoderma, and Cladosporium, all commonly found in terrestrial habitats and associated with marine invertebrates. We observed some unusual species in relation to the marine environment, such as Clonostachys rosea and Neopestalotiopsis clavispora, most of them related to plants, either as saprophytic or pathogenic, suggesting that these species were transported from the surrounding terrestrial environment to the reefs. In addition, some isolates represent possible undescribed species, reinforcing the importance of studying the marine environment in relation to its ecological and biotechnological importance.

Ubiquitous giants: a plethora of giant viruses found in Brazil and Antarctica.

BACKGROUND: Since the discovery of giant viruses infecting amoebae in 2003, many dogmas of virology have been revised and the search for these viruses has been intensified. Over the last few years, several new groups of these viruses have been discovered in various types of samples and environments.In this work, we describe the isolation of 68 giant viruses of amoeba obtained from environmental samples from Brazil and Antarctica. METHODS: Isolated viruses were identified by hemacolor staining, PCR assays and electron microscopy (scanning and/or transmission). RESULTS: A total of 64 viruses belonging to the Mimiviridae family were isolated (26 from lineage A, 13 from lineage B, 2 from lineage C and 23 from unidentified lineages) from different types of samples, including marine water from Antarctica, thus being the first mimiviruses isolated in this extreme environment to date. Furthermore, a marseillevirus was isolated from sewage samples along with two pandoraviruses and a cedratvirus (the third to be isolated in the world so far). CONCLUSIONS: Considering the different type of samples, we found a higher number of viral groups in sewage samples. Our results reinforce the importance of prospective studies in different environmental samples, therefore improving our comprehension about the circulation anddiversity of these viruses in nature.

Carlosrosaea hohenbergiae sp. nov. and Carlosrosaea aechmeae sp. nov., two tremellaceous yeasts isolated from bromeliads in north-eastern Brazil.

Yeast surveys associated with different bromeliads in north-eastern Brazil led to the proposal of two novel yeast species, Carlosrosaea hohenbergiae sp. nov. and Carlosrosaea aechmeae sp. nov., belonging to the Tremellales clade (Agaricomycotina, Basidiomycota). Analysis of the sequences of the internal transcribed spacer (ITS) region and D1/D2 domain of the LSU rRNA gene suggested an affinity with a phylogenetic lineage that includes recently reclassified Carlosrosaeavrieseae. Six isolates of the novel species were obtained from different bromeliad species collected in three Atlantic Forest fragments in Alagoas state, Brazil. Ca. hohenbergiae sp. nov. differs by 69 and 12 nucleotide substitutions in the ITS and D1/D2 domain, respectively, from Ca. vrieseae. The type strain is UFMG-CM-Y405T (=BSB 34T=CBS 14563T), Mycobank 819227. Ca. aechmeae sp. nov. is represented by one strain isolated from Aechmea constantinii leaves. Ca. aechmeae sp. nov. differs from the related species Ca. hohenbergiae and Ca. vrieseae by 36 and 65 nucleotide substitutions, respectively, in the ITS region and by 12 and 15 nucleotide substitutions in the D1/D2 domain, respectively. The type strain of Ca. aechmeae sp. nov. is UFMG-CM-Y6095T (=BM 94T=CBS 14578), Mycobank 819228.

Susceptibility to antifungal agents and enzymatic activity of Candida haemulonii and Cutaneotrichosporon dermatis isolated from soft corals on the Brazilian reefs.

Candida is a common fungus with the capacity to cause infections in humans. However, most studies have concentrated on clinical isolates and little is known about the identity, ecology and drug resistance of free living species/strains. Here, we isolate eight strains of Candida haemulonii and four strains of Cutaneotrichosporon dermatis from three marine cnidarian zoanthids species (Palythoa caribaeorum, Palythoa variabilis and Zoanthus sociatus) collected from Brazilian coral reefs. Strains were identified by sequencing of the D1/D2 domain LSU rDNA and ITS region. We tested these environmental isolates for their capacity to grow in media with increasing concentration of NaCl, capacity to grow in different temperatures, enzymatic activity and antifungal susceptibility. For C. haemulonii, all strains strongly produced gelatinase, esterase and albuminase and were either able to express lipase, phospholipase and keratinase, but not express urease and DNase. The strains were able to grow at 37 °C, but not at 39 °C, and except for LMS 40, all of them could grow in a 10 % NaCl medium. All isolates were resistant to all antifungals tested, with exception for ketoconazole and tioconazole (MIC = 2 µg/mL). For C. dermatis, all strains could grow at 39 °C and could not express phospholipase, keratinase or gelatinase. However, all were capable of expressing urease, lipase and esterase. Three out of four strains could grow in a 10 % NaCl medium, but none grew in a 30 % NaCl medium. The strains showed high values of minimal inhibitory concentration. LMPV 90 was resistant to tioconazole, terbinafine, fluconazole and posaconazole, and LMS 38 was resistant to all antifungal agents tested. We discuss the characterization of C. haemulonii and C. dermatis as a possible emerging pathogen due to its animal-related enzymatic arsenal and antifungal resistance.

Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov., two tremellaceous yeast species from Brazil.

Two yeast species, Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov., in the family Rhynchogastremataceae of the Tremellales are proposed. The two species are related to six species of the genus Papiliotrema: Papiliotrema aureus, P. flavescens, P. terrestris, P. baii, P. ruineniae and P. wisconsinensis. The novel species are proposed on the basis of the sequence-based phylogenetic species concept with analysis of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region. A total of 16 strains of Papiliotrema leoncinii sp. nov. were obtained from freshwater and bromeliad leaves collected in Brazil. Papiliotrema leoncinii sp. nov. differs by 11, 12, 16, 14, 11 and 13 substitutions in the D1/D2 domain from the related species P. aureus, P. flavescens, P. terrestris, P. baii, P. ruineniae and P. wisconsinensis, respectively. Differences of 11 substitutions and 21 or more substitutions in ITS regions were found when the sequences of Papiliotrema leoncinii sp. nov. were compared with P. wisconsinensis and its closest relatives. The type strain of Papiliotrema leoncinii sp. nov. is UFMG-CM-Y374T (=CBS 13918T). Papiliotrema miconiae sp. nov. is represented by two strains isolated from a flower of Miconia sp. and a water sample in Brazil. Papiliotrema miconiae sp. nov. differs from the related species P. aureus and P. ruineniae by eight substitutions, from P. flavescens and P. terrestris by 11 substitutions, from P. baii by 10 substitutions and from P. wisconsinensis by 6 substitutions in the D1/D2 domain, and by 7 substitutions from P. wisconsinensis and more than 19 substitutions in the ITS region from its closest relatives. The type strain of Papiliotrema miconiae sp. nov. is CBS 8358T (ML 3666T=DBVPG-4492T). The MycoBank numbers for Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov. are MB 813594 and MB 814882, respectively.

Bullera vrieseae sp. nov., a tremellaceous yeast species isolated from bromeliads.

Two independent surveys of yeasts associated with different bromeliads in different Brazilian regions led to the proposal of a novel yeast species, Bullera vrieseae sp. nov., belonging to the Tremellales clade (Agaricomycotina, Basidiomycota). Analysis of the sequences in the internal transcribed spacer (ITS) region and D1/D2 domain of the LSU rRNA gene suggested affinity to a phylogenetic lineage that includes Bullera miyagiana and Bullera sakaeratica. Six isolates of the novel species were obtained from different bromeliads and regions in Brazil. Sequence analysis of the D1/D2 domains of the large subunit of the rRNA gene showed that the novel species differs from B. miyagiana and B. sakaeratica by 85 and 64 nt substitutions, respectively and by more than 75 nt substitutions in the ITS region. Phenotypically, Bullera vrieseae sp. nov. can be distinguished from both species based on the assimilation of meso-erythritol, which was negative for B. vrieseae sp. nov. but positive for the others, assimilation of d-glucosamine, which was positive for B. vrieseae sp. nov. but negative for B. miyagiana and of l-sorbose, which was negative for B. vrieseae sp. nov. but positive for B. sakaeratica. The novel species Bullera vrieseae sp. nov. is proposed to accommodate these isolates. The type strain of Bullera vrieseae sp. nov. is UFMG-CM-Y379T (BRO443T; ex-type CBS 13870T).

Enzymatic Activity and Susceptibility to Antifungal Agents of Brazilian Environmental Isolates of Hortaea werneckii.

Four strains of Hortaea werneckii were isolated from different substrates in Brazil (a salt marsh macrophyte, a bromeliad and a marine zoanthid) and had their identification confirmed by sequencing of the 26S rDNA D1/D2 domain or ITS region. Most of the strains were able to express amylase, lipase, esterase, pectinase and/or cellulase, enzymes that recognize components of plant cells as substrates, but did not express albuminase, keratinase, phospholipase and DNAse, whose substrates are animal-related. Urease production was positive for all isolates, while caseinase, gelatinase and laccase production were variable among the strains. All the strains grew in media containing up to 30% NaCl. We propose that the primary substrate associated with H. werneckii is plant-related, in special in saline environments, where the fungus may live as a saprophyte and decomposer. Infection of animal-associated substrates would be secondary, with the fungus acting as an opportunistic animal pathogen. All strains were resistant to fluconazole and presented high MIC for amphotericin B, while they were susceptible to all the other antifungal agents tested.

Comparative genome analysis of entomopathogenic fungi reveals a complex set of secreted proteins.

BACKGROUND: Metarhizium anisopliae is an entomopathogenic fungus used in the biological control of some agricultural insect pests, and efforts are underway to use this fungus in the control of insect-borne human diseases. A large repertoire of proteins must be secreted by M. anisopliae to cope with the various available nutrients as this fungus switches through different lifestyles, i.e., from a saprophytic, to an infectious, to a plant endophytic stage. To further evaluate the predicted secretome of M. anisopliae, we employed genomic and transcriptomic analyses, coupled with phylogenomic analysis, focusing on the identification and characterization of secreted proteins. RESULTS: We determined the M. anisopliae E6 genome sequence and compared this sequence to other entomopathogenic fungi genomes. A robust pipeline was generated to evaluate the predicted secretomes of M. anisopliae and 15 other filamentous fungi, leading to the identification of a core of secreted proteins. Transcriptomic analysis using the tick Rhipicephalus microplus cuticle as an infection model during two periods of infection (48 and 144 h) allowed the identification of several differentially expressed genes. This analysis concluded that a large proportion of the predicted secretome coding genes contained altered transcript levels in the conditions analyzed in this study. In addition, some specific secreted proteins from Metarhizium have an evolutionary history similar to orthologs found in Beauveria/Cordyceps. This similarity suggests that a set of secreted proteins has evolved to participate in entomopathogenicity. CONCLUSIONS: The data presented represents an important step to the characterization of the role of secreted proteins in the virulence and pathogenicity of M. anisopliae.

Hannaella pagnoccae sp. nov., a tremellaceous yeast species isolated from plants and soil.

Several independent surveys of yeasts associated with different plant materials and soil led to the proposal of a novel yeast species belonging to the Tremellales clade (Agaricomycotina, Basidiomycota). Analysis of the sequences of the D1/D2 domains and internal transcribed spacer region of the large subunit of the rRNA gene suggested affinity to a phylogenetic lineage that includes Hannaella coprosmaensis, Hannaella oryzae and Hannaella sinensis. Thirty-two isolates were obtained from different sources, including bromeliads, nectar of Heliconia psittacorum (Heliconiaceae), flowers of Pimenta dioica (Myrtaceae), roots and leaves of sugar cane (Saccharum spp.) in Brazil, leaves of Cratoxylum maingayi, Arundinaria pusilla and Vitis vinifera in Thailand, soil samples in Taiwan, and prairie soil in the USA. Sequence analysis of the D1/D2 domains of the large subunit of the rRNA gene showed that the novel species differs from Hannaella coprosmaensis and Hannaella oryzae by 36 and 46 nt substitutions, respectively. A novel species is suggested to accommodate these isolates, for which the name Hannaella pagnoccae sp. nov. is proposed. The type strain is BI118(T) ( = CBS 11142(T) = ATCC MYA-4530(T)).

Susceptibility of species within the Sporothrix schenckii complex to a panel of killer yeasts.

The Sporothrix schenckii complex is the etiologic agent of sporotrichosis, a subacute or chronic mycosis which can affect humans and animals. Killer yeasts have been used in the medical field for development of novel antimycotics and biotyping of pathogenic fungi. The action of 18 killer yeasts on the growth of 88 characterized S. schenckii, Sporothrix globosa, Sporothrix brasiliensis, and Sporothrix mexicana clinical and environmental isolates was evaluated. Killer studies were performed on Petri dishes containing cheese black starch agar. The yeasts Candida catenulata (QU26, QU31, QU127, LV102); Trichosporon faecale (QU100); Trichosporon japonicum (QU139); Kluyveromyces lactis (QU30, QU99, QU73); Kazachstania unispora (QU49), Trichosporon insectorum (QU89), and Kluyveromyces marxianus (QU103) showed activity against all strains of the S. schenckii complex tested. Observation by optical microscopy of S. brasiliensis 61 within the inhibition haloes around the colonies of the killer yeasts QU100, QU139, and LV102 showed that there was no conidiation, but there was hyphal proliferation. The toxins were fungistatic against S. brasiliensis 61. There was no difference in susceptibility to the toxins among the S. schenckii species complex. Further investigations are necessary to clearly establish the mechanism of action of the toxins.

Brazilian mangrove sediments as a source of biosurfactant-producing yeast Pichia pseudolambica for bioremediation.

This work highlights the biosurfactant production potential of yeasts from mangroves in northeastern Brazil. The biosurfactants were evaluated by their emulsifying capacity (EI24), with 6 isolates showing values between 50% and 62%. Surfactant properties from crude extract were measured using drop collapse, oil displacement, Parafilm® M, surface tension and critical micellar concentration tests. The effects of temperature, salinity, pH, and the ability to emulsify different hydrocarbons were analyzed, showing a promising potential of the yeast species investigated to tolerance to high temperatures and acidic pH, in addition to emulsifying different sources of hydrocarbons with environmental impact. It is important to note that the Pichia pseudolambica isolates showed a remarkable ability to reduce the surface tension of water, from 70.82 mN/m to 36.47 mN/m. In addition, the critical micellar concentration (CMC) values ranged from 7 to 16 mg/mL, highlighting the promising surfactant activity of these isolates for future applications. It was identified that the biosurfactant adhered to the yeast cell wall, and FTIR and 1H NMR spectroscopy analysis was carried out on the yeast biomass and its post-sonication supernatant. The results indicate the presence of characteristic functional groups and peaks found in biosurfactants of a glycolipid nature. Taking together the results reveals the promising potential of biosurfactant biosynthesis of P. pseudolambica yeast, a trait not reported in the literature so far for this species. P. pseudolambica presents a relevant metabolic potential for alternative substrate use and resilience to adverse conditions that could enable it to produce biosurfactants for the biotechnological remediation of areas contaminated by oil derivatives. The metabolic properties herein investigated, together with their presence in Brazilian mangroves, make P. pseudolambica an emerging candidate for developing industrial processes and sustainable strategies for the recovery of ecosystems impacted by oil spills, being positioned as a sustainable alternative to conventional surfactants.

Biosurfactants production by marine yeasts isolated from zoanthids and characterization of an emulsifier produced by Yarrowia lipolytica LMS 24B.

The present study investigates the potential for biosurfactant production of 19 marine yeast species obtained from zoanthids. Using the emulsification index test to screen the samples produced by the marine yeasts, we verified that five isolates exhibited an emulsification index ≥50%. Additional tests were performed on such isolates, including oil displacement, drop collapse, Parafilm M assay, and surface tension measurement. The tolerance of produced biosurfactants for environmental conditions was also analyzed, especially considering the media's temperature, pH, and salinity. Moreover, the surfactant's ability to emulsify different hydrocarbon sources and to metabolize kerosene as the sole carbon source was evaluated in vitro. Our results demonstrate that yeast biosurfactants can emulsify hydrocarbon sources under different physicochemical conditions and metabolize kerosene as a carbon source. Considering the Yarrowia lipolytica LMS 24B as the yeast model for biosurfactant production from the cell's wall biomass, emulsification indexes of 61.2% were obtained, even at a high temperature of 120 °C. Furthermore, the Fourier-transform middle infrared spectroscopy (FTIR) analysis of the biosurfactant's chemical composition revealed the presence of distinct functional groups assigned to a glycoprotein complex. Considering the status of developing new bioproducts and bioprocesses nowadays, our findings bring a new perspective to biosurfactant production by marine yeasts, especially Y. lipolytica LMS 24B. In particular, the presented results validate the relevance of marine environments as valuable sources of genetic resources, i.e., yeast strains capable of metabolizing and emulsifying petroleum derivatives.