Isolated from Vinasse-Irrigated Sugarcane Plantation Soil: A Promising Yeast for Ethanol and Xylitol Production in Biorefineries.

The production of fuels and other industrial products from renewable sources has intensified the search for new substrates or for the expansion of the use of substrates already in use, as well as the search for microorganisms with different metabolic capacities. In the present work, we isolated and tested a yeast from the soil of sugarcane irrigated with vinasse, that is, with high mineral content and acidic pH. The strain of URM 8365 was able to ferment glucose, but the use of xylose occurred when some oxygenation was provided.

A comparative study between Fusarium solani and Neocosmospora vasinfecta revealed differential profile of fructooligosaccharide production.

Fructooligosaccharides (FOS) are fructose-based oligosaccharides employed as additives to improve the food's nutritional and technological properties. The rhizosphere of plants that accumulate fructopolysaccharides as inulin has been revealed as a source of filamentous fungi. These fungi can produce FOS either by inulin hydrolysis or by biosynthesis from sucrose, including unusual FOS with enhanced prebiotic properties.

The Saccharomyces cerevisiae Ncw2 protein works on the chitin/β-glucan organisation of the cell wall.

The NCW2 gene was recently described as encoding a GPI-bounded protein that assists in the re-modelling of the Saccharomyces cerevisiae cell wall (CW) and in the repair of damage caused by the polyhexamethylene biguanide (PHMB) polymer to the cell wall. Its absence produces a re-organization of the CW structure that result in resistance to lysis by glucanase. Hence, the present study aimed to extend the analysis of the Ncw2 protein (Ncw2p) to determine its physiological role in the yeast cell surface.

Gene regulation of the Lactobacillus vini in response to industrial stress in the fuel ethanol production.

The industrial ethanol fermentation imposes several stresses to microorganisms. However, some bacterial species are well adapted and manage to endure these harmful conditions. Lactobacillus vini is one of the most found bacteria in these environments, indicating the existence of efficient tolerance mechanisms.

The effects of the Ncw2 protein of Saccharomyces cerevisiae on the positioning of chitin in response to cell wall damage.

The recently described NCW2 gene encodes a protein that is assumed to be located in the cell wall (CW). This protein was proposed to participate in the repair of CW damages induced by polyhexamethylene biguanide (PHMB). However, much of the information on the biological function(s) of Ncw2p still remains unclear.

Lactobacillus vini: mechanistic response to stress by medium acidification.

This work describes the response of Lactobacillusvini, a bacterium found as a contaminant in winemaking and fuel ethanol fermentation processes, to acid stress caused by inorganic or weak organic acids. First, we observed for the first time that bacterial cells become resistant to lysis by lysozyme when submitted to acidic stress. Then, the predicted intracellular acidification can be reversed by the presence of arginine, histidine and glutamine.

Respiratory deficiency in yeast mevalonate kinase deficient may explain MKD-associate metabolic disorder in humans.

Mevalonate kinase deficiency (MKD) an orphan drug rare disease affecting humans with different clinical presentations, is still lacking information about its pathogenesis; no animal or cell model mimicking the genetic defect, mutations at MVK gene, and its consequences on the mevalonate pathway is available. Trying to clarify the effects of MVK gene impairment on the mevalonate pathway we used a yeast model, the erg12-d mutant strain Saccharomyces cerevisiae (orthologous of MKV) retaining only 10% of mevalonate kinase (MK) activity, to describe the effects of reduced MK activity on the mevalonate pathway. Since shortage of isoprenoids has been described in MKD, we checked this observation using a physiologic approach: while normally growing on glucose, erg12-d showed growth deficiency in glycerol, a respirable carbon source, that was not rescued by supplementation with non-sterol isoprenoids, such as farnesol, geraniol nor geranylgeraniol, produced by the mevalonate pathway.

NCW2, a Gene Involved in the Tolerance to Polyhexamethylene Biguanide (PHMB), May Help in the Organisation of β-1,3-Glucan Structure of Saccharomyces cerevisiae Cell Wall.

In the present work, we provide biological evidences supporting the participation of NCW2 gene in the mechanism responsible for cell tolerance to polyhexamethylene biguanide (PHMB), an antifungal agent. The growth rate of yeast cells exposed to this agent was significantly reduced in ∆ncw2 strain and the mRNA levels of NCW2 gene in the presence of PHMB showed a 7-fold up-regulation. Moreover, lack of NCW2 gene turns yeast cell more resistant to zymolyase treatment, indicating that alterations in the β-glucan network do occur when Ncw2p is absent.

Evidence for a Role for the Plasma Membrane in the Nanomechanical Properties of the Cell Wall as Revealed by an Atomic Force Microscopy Study of the Response of Saccharomyces cerevisiae to Ethanol Stress.

Unlabelled: A wealth of biochemical and molecular data have been reported regarding ethanol toxicity in the yeast Saccharomyces cerevisiae However, direct physical data on the effects of ethanol stress on yeast cells are almost nonexistent. This lack of information can now be addressed by using atomic force microscopy (AFM) technology. In this report, we show that the stiffness of glucose-grown yeast cells challenged with 9% (vol/vol) ethanol for 5 h was dramatically reduced, as shown by a 5-fold drop of Young's modulus.

Genetic Interaction between HOG1 and SLT2 Genes in Signalling the Cellular Stress Caused by Sulphuric Acid in Saccharomyces cerevisiae.

In fuel ethanol production, recycling of yeast biomass includes treatment of cells with diluted sulphuric acid in order to control bacterial population. However, this strategy might lead to a loss of cell viability, with potential negative consequences to the fermentation yield. In a recent paper we showed that the proteins Slt2 and Hog1 are essential for yeast tolerance to sulphuric acid.

Transcriptomic response of Saccharomyces cerevisiae for its adaptation to sulphuric acid-induced stress.

In bioethanol production plants, yeast cells are generally recycled between fermentation batches by using a treatment with sulphuric acid at a pH ranging from 2.0 to 2.5.

The resistance of the yeast Saccharomyces cerevisiae to the biocide polyhexamethylene biguanide: involvement of cell wall integrity pathway and emerging role for YAP1.

Background: Polyhexamethylene biguanide (PHMB) is an antiseptic polymer that is mainly used for cleaning hospitals and pools and combating Acantamoeba infection. Its fungicide activity was recently shown by its lethal effect on yeasts that contaminate the industrial ethanol process, and on the PE-2 strain of Saccharomyces cerevisiae, one of the main fermenting yeasts in Brazil. This pointed to the need to know the molecular mechanism that lay behind the cell resistance to this compound.

Polyhexamethyl biguanide can eliminate contaminant yeasts from fuel-ethanol fermentation process.

Industrial ethanol fermentation is a non-sterile process and contaminant microorganisms can lead to a decrease in industrial productivity and significant economic loss. Nowadays, some distilleries in Northeastern Brazil deal with bacterial contamination by decreasing must pH and adding bactericides. Alternatively, contamination can be challenged by adding a pure batch of Saccharomyces cerevisiae-a time-consuming and costly process.