Induction of Phytoalexins Gliceoline and Proteins Related to Defense in Soybean Cotyledon Treated With Yeast

Yeasts can induce mechanisms of plant resistance due to compounds with eliciting characteristics, so the aim of this work was to evaluate the effect of yeast on the induction of phytoalexins gliceoline, peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase from soy cotyledons. To determine the defense enzymes, soybean seeds were sown and the cotyledons treated with sterile distilled water, Cryptococcus laurentii (AH 03-1), Pichia guilliermondii (AH 16-2), Rhodotorula glutinis (AH 14-3), Sporidiobolus johnsonii (AH 16-1) and Zygoascus hellenicus (AH 14-1). Biochemical analyzes of the formation of phytoalexins and the activity of the enzymes peroxidase, polyphenoloxidase, phenylalanine ammonia-lyase and total proteins were performed. For phytoalexins glycerolins the yeasts Cryptococcus laurentii (AH 03-1) and Zygoascus hellenicus (AH 14-1) promoted an increase of 83.65% and 78.75% in the formation of this compound. Cryptococcus laurentii (AH 03-1) increased peroxidase activity by 36.84%, while for polyphenoloxidase, the Pichiaguilliermondii e yeasts (AH 16-2), Rhodotorula glutinis (AH 14-3), Sporidiobolus johnsonii (AH 16-1) and Zygoascus hellenicus (AH 14-1), increased the activity of this enzyme by 33.33%, 28.00%, 33.33% and 33.33%, respectively. For phenylalanine ammonia-lyase, Cryptococcus laurentii (AH 03-1) and Zygoascushellenicus (AH 14-1) promoted an increase of 75.57% and 78.86%, respectively, in their activity. The results demonstrate the potential of yeasts studied in the induction of phytoalexins glyceolins and in the activity of peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase in soybean cotyledons.

Evaluation of Yeast Potential in the Biological Control of Colletotrichum orbiculare in Cucumber

This work aimed to evaluate the effect of the yeasts Candida albicans, Pichia guilliermondii, Rhodotorula glutinis, Saccharomyces cerevisiae and Zygoascus hellenicus in the control of anthracnose in cucumbers. The influence of volatile and non-volatile compounds on mycelial growth and the effect of cell suspension and culture filtrate on conidial germination were evaluated. In a greenhouse, yeasts were tested on cucumber cotyledons, one cotyledon being treated and the other not; afterwards both cotyledons were challenged with C. orbiculare. The severity of the disease in both cotyledons was assessed by determining biological control and resistance induction. The production of volatile compounds from the yeasts R. glutinis and C. albicans reduced the pathogen growth by 90.7 and 90.0%, respectively. The production of non-volatile compounds stimulated the pathogen development. Conidia germination was affected when exposed to cell suspension of all tested isolates, ranging from 43 to 75%. For the culture filtrate from Z. hellenicus, it reduced the conidia germination by 11.4%. In the in vivo test, on the treated cotyledon, the yeasts Z. hellenicus, R. glutinis and S. cerevisiae reduced the anthracnose severity by 52.5, 50.0 and 42.5%, respectively.

Performance Evaluation of Non-Saccharomyces in Wine Production

Wines with different tastes, aromas, colours and acceptability produced through the fermentative action of yeasts are consumed worldwide Several studies have centred on the use of Saccharomyces sp. as the choice yeast for fermentation due to its desirable characteristics; however, in recent years, researches are being focused on alternatives to Saccharomyces sp. This study however was aimed at carrying out a performance evaluation of wine produced by the fermentative action of non-Saccharomyces (Meyerozyma guilliermondii and Pichia guilliermondii). The wines were produced using a mixture of pineapple juice and blended banana pulp as substrate.The fermentation process comprised of two set ups: one was fermented by Meyerozyma guilliermondii strain 1621 and the other was fermented by Pichia guilliermondii strain PAX-PAT 18S. An organoleptic (sensory) evaluation of both wines produced was carried out to ascertain the quality of the wines in comparison to a commercial wine. This was done using a 9-point hedonic scale rating. The wines were evaluated for their organoleptic characteristics including aroma, colour, clarity, taste and overall acceptability. The wine fermented by Meyerozyma guilliermondii had mean values of 7.3, 7.0, 6.4, 3.8 and 6.1 for aroma, colour, clarity, taste and overall acceptability, respectively. The wine fermented by Pichia guilliermondii had mean values of 6.2, 7.1, 5.5, 4.7 and 5.9 for aroma, colour, clarity, taste and overall acceptability, respectively. The commercial wine had mean values of 4.7, 6.6, 7.4, 7.4 and 6.5 for aroma, colour, clarity, taste and overall acceptability, respectively. Statistically, there was significant difference between the aroma of the wines (P≤0.05) while there were no significant differences in colour, clarity, taste and overall acceptability of the wines. This study shows that acceptable wines can be produced using non-Saccharomyces yeasts like Meyerozyma guilliermondii and Pichia guilliermondii.

Screening of Yeast Cells for the Production of Wine from Banana and Pineapple Substrates

Wine, an alcoholic beverage is usually produced from juice of variety of fruits by the fermentative action of microorganisms particularly by yeasts. Several substrates such as pineapple, banana, watermelon, pawpaw and other fruits have been used to produce wine using Saccharomyces species. This study was undertaken using non- Saccharomyces to produce table wine with pineapple and banana fruits as substrates. Standard microbiological procedures were employed for yeasts cell isolation, sugar (sucrose) fermentation test, pH, ethanol, sucrose and glucose tolerance test were carried out respectively. Alcohol production by the yeasts was screened and the isolates were identified by genomic techniques. Twenty-two (22) yeasts isolated from palm wine (YW), banana (YB) and pineapple (YP) were screened for their ability to ferment sugar and fourteen (14) of the yeast isolates were positive while eight (8) were negative. The fourteen (14) isolates were further screened for their ability to tolerate pH, ethanol, sucrose and glucose. Tolerance tests for these fourteen (14) yeast isolates recorded values between a range of 3.0-5.0, 0-10% v/v, 5-20% w/v and 5-25% w/v for pH, ethanol, sucrose and glucose concentrations respectively. Statistically, there was a significant difference in the interaction effect for pH, ethanol, sucrose and glucose tolerance (OD600 nm) for yeast isolates at p value ≤ 0.0001. Five (5) yeast isolates had high tolerance ability to pH, ethanol, sucrose and glucose and were further screened for their ability to produce alcohol. The five (5) yeast isolates were identified as Meyerozyma guilliermondii strain 1621, Pichia guilliermondii strain PX-PAT, Meyerozyma caribbica strain Kw 1S7Y2, Meyerozyma caribbica strain Y-27400, Kodamaea ohmeri strain ww1-1 and they produced alcohol content of 7.6%, 6.5%, 2.9%, 2.5% and 0.3% respectively. Meyerozyma guilliermondii strain 1621 and Pichia guilliermondii strain PX-PAT 18 S isolated from palm wine exhibited good characteristics and produced high quantity of alcohol and are suitable for alcohol fermentation of substrates for wine production.

Effect of Candida intermedia LAMAP1790 Antimicrobial Peptides against Wine-Spoilage Yeasts Brettanomyces bruxellensis and Pichia guilliermondii

Wine spoilage yeasts are one of the main issues in the winemaking industry, and the control of the Brettanomyces and Pichia genus is an important goal to reduce economic loses from undesired aromatic profiles. Previous studies have demonstrated that Candida intermedia LAMAP1790 produces antimicrobial peptides of molecular mass under 10 kDa with fungicide activity against Brettanomyces bruxellensis, without affecting the yeast Saccharomyces cerevisiae. So far, it has not been determined whether these peptides show biocontroller effect in this yeast or other spoilage yeasts, such as Pichia guilliermondii. In this work, we determined that the exposure of B. bruxellensis to the low-mass peptides contained in the culture supernatant of C. intermedia LAMAP1790 produces a continuous rise of reactive oxygen species (ROS) in this yeast, without presenting a significant effect on membrane damage. These observations can give an approach to the antifungal mechanism. In addition, we described a fungicide activity of these peptides fraction against two strains of P. guilliermondii in a laboratory medium. However, carrying out assays on synthetic must, peptides must show an effect on the growth of B. bruxellensis. Moreover, these results can be considered as a start to develop new strategies for the biocontrol of spoilage yeast.