Modulation of quorum sensing activity by copper sulfate, potassium dichromate, and cadmium chloride in biosensor strains.

Beyond their biological roles, metals have a strong impact on the environment. It has been reported that metals are also inhibitory of Quorum Sensing (QS) mechanisms, ones of the best characterized signaling systems in bacteria and fungi. We analyzed the effect of CuSO4, CdCl2, and K2Cr2O7, on QS systems sharing or differing in the bacterial host or the QS signal.

Vinasse odyssey: sugarcane vinasse remediation and laccase production by Trametes sp. immobilized in polyurethane foam.

Vinasse is a high pollutant liquid residue from bioethanol production. Due to its toxicity, most vinasse is used not disposed of in water bodies but employed for the fertigation of sugarcane crops, potentially leading to soil salinization or heavy metal deposition. The anaerobic digestion of vinasse for energy production is the main alternative to fertigation, but the process cannot eliminate colored compounds such as melanoidins, caramels, or phenolic compounds.

Fatty acids profiles and estimation of the biodiesel quality parameters from Rhodotorula spp. from Antarctica.

Objective: Oleaginous yeasts are a renewable and alternative source of oil for third-generation biodiesel. This work aimed to evaluate the effects of glucose concentration (30-100 g L) on growth, lipid synthesis, and fatty acids (FA) profile of three Rhodotorula spp. (R.

Genome-wide overview of HP-2023, new insights into its mechanism of dye discoloration.

HP-2023 completely discolorised Reactive Black 5 (200 mg/l) in 24 h. Manganese peroxidase and phenoloxidase, but no laccase activities were detected throughout the incubation. Total aromatic amines in media with Reactive Black 5 decreased 83% after 24 h, supporting an oxidative mechanism of azo dye discoloration.

Bioremediation strategies for chromium removal: Current research, scale-up approach and future perspectives.

Industrial applications and commercial processes release a lot of chromium into the environment (soil, surface water or atmosphere) and resulting in serious human diseases because of their toxicity. Biological Cr-removal offers an alternative to traditional physic-chemical methods. This is considered as a sustainable technology of lower impact on the environment.

Optimization and mechanisms for biodecoloration of a mixture of dyes by Trichosporon akiyoshidainum HP 2023.

Trichosporon akiyoshidainum HP2023 is a basidiomycetous yeast isolated from Las Yungas rainforest (Tucumán, Argentina) and selected based on its outstanding textile-dye-decolorizing ability. In this work, the decolorization process was optimized using Reactive Black 5 as dye model. Lactose and urea were chosen as carbon and nitrogen sources through a one-at-time approach.

Biodecoloration of Reactive Black 5 by the methylotrophic yeast Candida boidinii MM 4035.

Azo dyes are extensively used in textile dyeing and other industries. Effluents of dying industries are specially colored and could cause severe damage to the environment. The anaerobic treatment of textile dying effluents is nowadays the preferred option, but it could generate carcinogenic aromatic amines.

Phenol degradation and heavy metal tolerance of Antarctic yeasts.

In cold environments, biodegradation of organic pollutants and heavy metal bio-conversion requires the activity of cold-adapted or cold-tolerant microorganisms. In this work, the ability to utilize phenol, methanol and n-hexadecane as C source, the tolerance to different heavy metals and growth from 5 to 30 °C were evaluated in cold-adapted yeasts isolated from Antarctica. Fifty-nine percent of the yeasts were classified as psychrotolerant as they could grow in all the range of temperature tested, while the other 41% were classified as psychrophilic as they only grew below 25 °C.

Oleaginous yeasts from Antarctica: Screening and preliminary approach on lipid accumulation.

The capability of 17 Rhodotorula spp. isolated from Antarctica to accumulate intracellular lipids in nitrogen-limited medium was investigated. As results, 10 isolates were selected by Nile red staining, while 12 isolates were selected as oleaginous by analysis of total lipid content (20.

[Biomineralization of copper in Candida fukuyamaensis RCL-3].

Candida fukuyamaensis RCL-3 yeast has the ability to decrease copper concentration in a culture medium. High copper concentrations change the cell color from white/cream to brown. The effect of color change ceases with the addition of KCN or when cells are grown in a culture medium without sulfate ions.

Disentangling metabolic pathways involved in copper resistance in Candida fukuyamaensis RCL-3 indigenous yeast.

Candida fukuyamaensis RCL-3 yeast strain isolated from a copper filter plant is able to lower copper concentration in culture medium. In the present study, effect of copper in proteins expression and mechanisms involved in copper resistance were explored using comparative proteomics. Mono-dimensional gel electrophoresis revealed differential band expressions between cells grown with or without copper.

Gluconic acid produced by Gluconacetobacter diazotrophicus Pal5 possesses antimicrobial properties.

Gluconic acid is produced in large quantities by the endophytic and diazotrophic bacterium Gluconacetobacter diazotrophicus Pal5. This organic acid derives from direct oxidation of glucose by a pyrroloquinoline-quinone-linked glucose dehydrogenase in this plant growth-promoting bacterium. In the present article, evidence is presented showing that gluconic acid is also responsible for the antimicrobial activity of G.

Gluconacetobacter diazotrophicus PAL5 possesses an active quorum sensing regulatory system.

The endophytic bacterium Gluconacetobacter diazotrophicus colonizes a broad range of host plants. Its plant growth-promoting capability is related to the capacity to perform biological nitrogen fixation, the biosynthesis of siderophores, antimicrobial substances and the solubilization of mineral nutrients. Colonization of and survival in these endophytic niche requires a complex regulatory network.

Polyphenolic substrates and dyes degradation by yeasts from 25 de Mayo/King George Island (Antarctica).

Antarctica offers a range of extreme climatic conditions, such as low temperatures, high solar radiation and low nutrient availability, and constitutes one of the harshest environments on Earth. Despite that, it has been successfully colonized by ’cold-loving’ fungi, which play a key role in decomposition cycles in cold ecosystems. However, knowledge about the ecological role of yeasts in nutrient or organic matter recycling/mineralization remains highly fragmentary.

Effects of thermal, alkaline and ultrasonic treatments on scleroglucan stability and flow behavior.

Aqueous solutions (0.2%, w/v) of scleroglucans from Sclerotium rolfsii ATCC 201126 from different cultivation time or purification protocol (EPS I, EPS II, EPSi) as well as a commercial scleroglucan (LSCL) exhibited different sensitivity against thermal (65, 95 and 150°C), ultrasonic (1, 5 and 10 min; 20% amplitude) or alkaline (0.01-0.

Scleroglucan compatibility with thickeners, alcohols and polyalcohols and downstream processing implications.

Thickening capacity and compatibility of scleroglucan with commercial thickeners (corn starch, gum arabic, carboxymethylcellulose, gelatin, xanthan and pectin), glycols (ethylene glycol and polyethylene glycol), alcohols (methanol, ethanol, 1-propanol and isopropanol) and polyalcohols (sorbitol, xylitol and mannitol) was explored. Exopolysaccharides (EPSs) from Sclerotium rolfsii ATCC 201126 and a commercial scleroglucan were compared. Compatibility and synergism were evaluated taking into account rheology, pH and sensory properties of different thickener/scleroglucan mixtures in comparison with pure solutions.

Synergistic antifungal activity of statin-azole associations as witnessed by Saccharomyces cerevisiae- and Candida utilis-bioassays and ergosterol quantification.

Background: Frequent opportunist fungal infections and the resistance to available antifungal drugs promoted the development of new alternatives for treatment, like antifungal drug combinations.

Aims: This work aimed to detect the antifungal synergism between statins and azoles by means of an agar-well diffusion bioassay with Saccharomyces cerevisiae ATCC 32051 and Candida utilis Pr(1-2) as test strains.

Methods: Synergistic antifungal effects were tested by simultaneously adding a sub inhibitory concentration (SIC) of statin (atorvastatin, lovastatin, pravastatin, rosuvastatin or simvastatin) plus a minimal inhibitory concentration (MIC) of azole (clotrimazole, fluconazole, itraconazole, ketoconazole or miconazole) to yeast-embedded YNB agar plates, and a positive result corresponded to a yeast growth inhibition halo higher than that produced by the MIC of the azole alone.

Removal efficiency of Cr6+ by indigenous Pichia sp. isolated from textile factory effluent.

Resistance of the indigenous strains P. jadinii M9 and P. anomala M10, to high Cr(6+) concentrations and their ability to reduce chromium in culture medium was studied.

Optimization of culture medium composition for manganese peroxidase and tyrosinase production during Reactive Black 5 decolourization by the yeast Trichosporon akiyoshidainum.

Decolourization and degradation of the diazo dye Reactive Black 5 was carried out by the yeast Trichosporon akiyoshidainum. A nine-factor Plackett-Burman design was employed for the study and optimization of the decolourization process and production of manganese peroxidase (MnP) and tyrosinase activities. In the present study, 26 individual experiments were conducted and three responses were evaluated.

Proteomic study of the yeast Rhodotorula mucilaginosa RCL-11 under copper stress.

In order to understand the mechanism involved in Rhodotorula mucilaginosa RCL-11 resistance to copper a proteomic study was conducted. Atomic absorption spectroscopy showed that the copper concentration in the medium decreased from 0.5 to 0.

Identification of N-acyl homoserine lactones produced by Gluconacetobacter diazotrophicus PAL5 cultured in complex and synthetic media.

The endophytic diazotrophic Gluconacetobacter diazotrophicus PAL5 was originally isolated from sugarcane (Saccharum officinarum). The biological nitrogen fixation, phytohormones secretion, solubilization of mineral nutrients and phytopathogen antagonism allow its classification as a plant growth-promoting bacterium. The recent genomic sequence of PAL5 unveiled the presence of a quorum sensing (QS) system.

Unraveling the decolourizing ability of yeast isolates from dye-polluted and virgin environments: an ecological and taxonomical overview.

Microcosm assays with dye-amended culture media under a shot-feeding strategy allowed us to obtain 100 yeast isolates from the wastewater outfall channel of a dyeing textile factory in Tucumán (Argentina). Meanwhile, 63 yeast isolates were obtained from Phoebe porphyria (Laurel del monte) samples collected from Las Yungas rainforest (Tucumán), via a classical isolation scheme. Isolated yeasts, both from dye-polluted and virgin environments, were compared for their textile dye decolourization ability when cultured on solid and liquid media.

Cu(II) removal by Rhodotorula mucilaginosa RCL-11 in sequential batch cultures.

The present study explored the ability of the yeast Rhodotorula mucilaginosa RCL-11 to adapt to increasing Cu(II) concentrations, measuring oxidative stress through superoxide dismutase and catalase activity in two parallel sequential batch assays. One assay was performed in Erlenmeyer flasks without aeration and a second in a fermentor in which the dissolved oxygen was maintained at 30% saturation. Both assays were carried out by increasing Cu(II) concentrations in five sequential steps: 0; 0.

Responses of Candida fukuyamaensis RCL-3 and Rhodotorula mucilaginosa RCL-11 to copper stress.

The effect of high Cu(II) concentrations on superoxide dismutase (SOD) and catalase (CAT) activity in Candida fukuyamaensis RCL-3 and Rhodotorula mucilaginosa RCL-11, previously isolated from a copper filter at a mine plant in Argentina, was studied. Addition of 0.1, 0.