Survey of Hydrogen Sulphide Production by Wine Yeasts

2002 ◽  
Vol 65 (6) ◽  
pp. 1033-1037 ◽  
Author(s):  
A. MENDES-FERREIRA ◽  
A. MENDES-FAIA ◽  
C. LEÃO
Keyword(s):  
Hydrogen Sulphide ◽  
Reductase Activity ◽  
Grape Juice ◽  
Nitrogen Sources ◽  
Medium Composition ◽  
Growth Patterns ◽  
Rapid Screening ◽  
Wine Yeasts ◽  
Synthetic Media ◽  
Sulphite Reductase

Twenty-one strains of commercial wine yeasts and 17 non-Saccharomyces species of different provenance were surveyed for their ability to produce hydrogen sulphide in synthetic grape juice medium indicator agar with different nitrogen sources, as well as in natural grape juice. Bacto Biggy agar, a commercially available bismuth-containing agar, was used to compare our results with others previously reported in the literature. Under identical physiological conditions, the strains used in this study displayed similar growth patterns but varied in colony color intensity in all media, suggesting significant differences in sulphite reductase activity. Sulphite reductase activity was absent for only one strain of Saccharomyces cerevisiae. All other strains produced an off-odor to different extents, depending significantly (P <0.05) on medium composition. Within the same species of some non-Saccharomyces yeasts, strain variation existed as it did for Saccharomyces. In natural musts, strains fell into three major groups: (i) nonproducers, (ii) must-composition-dependent producers, and (iii) invariable producers. In synthetic media, the formation of sulphide by strains of S. cerevisiae results from the reduction of sulphate. Therefore, this rapid screening methodology promises to be a very useful tool for winemakers for determining the risk of hydrogen sulphide formation by a given yeast strain in a specific grape juice.

scholarly journals Ligninolytic enzyme production in Pleurotus eryngii depending on the medium composition and cultivation conditions

2005 ◽  
pp. 269-276
Author(s):  
Mirjana Stajic ◽  
Sonja Duletic-Lausevic ◽  
Jelena Vukojevic
Keyword(s):  
Nitrogen Concentration ◽  
Nitrogen Sources ◽  
Ligninolytic Enzyme ◽  
Medium Composition ◽  
Pleurotus Eryngii ◽  
Phenol Red ◽  
Cultivation Conditions ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Two Peaks

Pleurotus eryngii produced laccase (Lac) both under conditions of submerged fermentation (SF) and solid-state fermentation (SSF) using all of the investigated carbon and nitrogen sources, while significant peroxidases production occurred only under SSF conditions. The highest levels of Lac activity were found under SF conditions of dry ground mandarine peels (999.5 U/l). After purification of extracellular crude enzyme mixture of P. eryngii which was grown under SF conditions with dry ground mandarine peels it was revealed two peaks of Lac activity and one peak of activity against phenol red in absence of external Mn2+ which was very low (1.4 U/l). Results obtained by purification also showed that the levels of phenol red oxidation in absence of external Mn2+ were higher than phenol red oxidation levels in presence of external Mn2+. In the medium with the best carbon source for Lac production (dry ground mandarine peels), (NH4)2SO4, with a nitrogen concentration of 20 mM, was the most optimum nitrogen source among 8 investigated sources.

scholarly journals Effect of Nutritional Factors and Copper on the Regulation of Laccase Enzymes Production in Pleurotus ostreatus

2021 ◽  
Author(s):  
Dinary Durán-Sequeda ◽  
Daniela Suspes ◽  
Estibenson Maestre ◽  
Manuel Alfaro ◽  
Gumer Pérez ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Pleurotus Ostreatus ◽  
Culture Media ◽  
Nitrogen Sources ◽  
Fold Increase ◽  
Medium Composition ◽  
Copper Transporter ◽  
Nutritional Factors ◽  
Laccase Genes ◽  
Response Variables

This research aimed to establish the relationship between carbon-nitrogen nutritional factors and copper sulfate on laccase activity (LA) by Pleurotus ostreatus. Culture media composition was tested to choose the nitrogen source. Yeast extract (YE) was selected as a better nitrogen source than ammonium sulfate. Then, the effect of glucose and YE concentrations on biomass production and LA as response variables was evaluated using central composite experimental designs with and without copper. The results showed that the best culture medium composition was glucose 45 gL-1 and YE 15 gL-1, simultaneously optimizing these two response variables. The fungal transcriptome was obtained in this medium with or without copper, and the differentially expressed genes were found. Main up-regulated transcripts included three laccase genes (lacc2, lacc6, and lacc10) regulated by copper, whereas the principal down-regulated transcripts included a copper transporter (ctr1) and a regulator of nitrogen metabolism (nmr1). These results suggest that Ctr1, which facilitates the entry of copper in the cell, is regulated by nutrient-sufficiency conditions. Once inside, copper induces transcription of laccase genes. This finding could explain why a 10 to 20-fold increase in LA occurs with copper compared to cultures without copper when using the optimal concentration of YE as nitrogen sources.

scholarly journals Long-Term Adaption to High Osmotic Stress as a Tool for Improving Enological Characteristics in Industrial Wine Yeast

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 576 ◽  
Author(s):  
Gabriela Betlej ◽  
Ewelina Bator ◽  
Bernadetta Oklejewicz ◽  
Leszek Potocki ◽  
Anna Górka ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Grape Juice ◽  
Wine Yeast ◽  
Sensory Profile ◽  
Wine Yeasts ◽  
Adaptive Laboratory Evolution ◽  
Yeast Viability ◽  
Glycerol Synthesis ◽  
The Many

Industrial wine yeasts owe their adaptability in constantly changing environments to a long evolutionary history that combines naturally occurring evolutionary events with human-enforced domestication. Among the many stressors associated with winemaking processes that have potentially detrimental impacts on yeast viability, growth, and fermentation performance are hyperosmolarity, high glucose concentrations at the beginning of fermentation, followed by the depletion of nutrients at the end of this process. Therefore, in this study, we subjected three widely used industrial wine yeasts to adaptive laboratory evolution under potassium chloride (KCl)-induced osmotic stress. At the end of the evolutionary experiment, we evaluated the tolerance to high osmotic stress of the evolved strains. All of the analyzed strains improved their fitness under high osmotic stress without worsening their economic characteristics, such as growth rate and viability. The evolved derivatives of two strains also gained the ability to accumulate glycogen, a readily mobilized storage form of glucose conferring enhanced viability and vitality of cells during prolonged nutrient deprivation. Moreover, laboratory-scale fermentation in grape juice showed that some of the KCl-evolved strains significantly enhanced glycerol synthesis and production of resveratrol-enriched wines, which in turn greatly improved the wine sensory profile. Altogether, these findings showed that long-term adaptations to osmotic stress can be an attractive approach to develop industrial yeasts.

scholarly journals Phosphorus and Nitrogen Limitation as a Part of the Strategy to Stimulate Microbial Lipid Biosynthesis

2021 ◽  
Vol 11 (24) ◽  
pp. 11819
Author(s):  
Katarzyna Wierzchowska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska
Keyword(s):  
Lipid Accumulation ◽  
Nitrogen Sources ◽  
Phosphorus Limitation ◽  
Inorganic Phosphorus ◽  
Lipid Biosynthesis ◽  
Medium Composition ◽  
Bioreactor Culture ◽  
Biomass Growth ◽  
Cellular Lipid ◽  
Lipid Yield

Microbial lipids called a sustainable alternative to traditional vegetable oils invariably capture the attention of researchers. In this study, the effect of limiting inorganic phosphorus (KH2PO4) and nitrogen ((NH4)2SO4) sources in lipid-rich culture medium on the efficiency of cellular lipid biosynthesis by Y. lipolytica yeast has been investigated. In batch cultures, the carbon source was rapeseed waste post-frying oil (50 g/dm3). A significant relationship between the concentration of KH2PO4 and the amount of lipids accumulated has been revealed. In the shake-flask cultures, storage lipid yield was correlated with lower doses of phosphorus source in the medium. In bioreactor culture in mineral medium with (g/dm3) 3.0 KH2PO4 and 3.0 (NH4)2SO4, the cellular lipid yield was 47.5% (w/w). Simultaneous limitation of both phosphorus and nitrogen sources promoted lipid accumulation in cells, but at the same time created unfavorable conditions for biomass growth (0.78 gd.m./dm3). Increased phosphorus availability with limited cellular access to nitrogen resulted in higher biomass yields (7.45 gd.m./dm3) than phosphorus limitation in a nitrogen-rich medium (4.56 gd.m./dm3), with comparable lipid yields (30% and 32%). Regardless of the medium composition, the yeast preferentially accumulated oleic and linoleic acids as well as linolenic acid up to 8.89%. Further, it is crucial to determine the correlation between N/P molar ratios, biomass growth and efficient lipid accumulation. In particular, considering the contribution of phosphorus as a component of coenzymes in many metabolic pathways, including lipid biosynthesis and respiration processes, its importance as a factor in the cultivation of the oleaginous microorganisms was highlighted.

scholarly journals Lovastatin Production from Cunninghamella blakesleeana under Solid State Fermentation

2021 ◽  
Author(s):  
Janani Balraj ◽  
Thandeeswaran Murugesan ◽  
Vidhya Kalieswaran ◽  
Karunyadevi Jairaman ◽  
Devippriya Esakkimuthu ◽  
...  
Keyword(s):  
Solid State ◽  
Incubation Period ◽  
Solid State Fermentation ◽  
Carbon Sources ◽  
Experimental Studies ◽  
Nitrogen Sources ◽  
Medium Composition ◽  
Critical Parameters ◽  
Physical Parameters ◽  
Cunninghamella Blakesleeana

Abstract Our earlier paper had established the fact that new soil fungi known as Cunninghamella blakesleeana is potent enough to produce lovastatin significantly. At present, there are no reports on the media optimization for the lovastatin production. Hence, the objective is to optimize the fermentation conditions for lovastatin production by Cunninghamella blakesleeana under Solid State fermentation (SSF) condition through screening the critical factors by one factor at a time and then, optimize the factors selected from screening using statistical approaches. SSF was carried using the pure culture of Cunninghamella blakesleeana KP780148.1 with wheat bran as substrate. Initial screening was performed for physical parameters, carbon sources and nitrogen sources and then optimized the selected parameters through PBD and BBD. Screening result indicated the optimum values of the analysed parameter for the maximal production of lovastatin by Cunninghamella blakesleeana were selected. Out of the nine factors MgSO4, (NH4)2SO4, pH and Incubation period were found to influence the lovastatin production significantly after PBD. The optimal levels of these variables and the effect of their mutual interactions on lovastatin production were determined using BBD surface design. The optimum medium composition was found to be MgSO4(0.2 g/L), (NH4)2 SO4 (12.5 g/L), pH (6) and Incubation period (7 days). Experimental studies showed a yield of 7.39 mg/g at the above optimized conditions which were observed to be very nearby to the predicted value and hence the model was successfully validated. Hence, this is the first report on the optimization of critical parameters for lovastatin production by Cunninghamella blakesleeana.

Tracking sources of selected diamonds from Southern Africa based on carbon isotopic and chemical impurities

2017 ◽  
Vol 120 (3) ◽  
pp. 371-384
Author(s):  
A.T. Kidane ◽  
M. Koch-Müller ◽  
M. Wiedenbeck ◽  
M. J. de Wit
Keyword(s):  
South Africa ◽  
Nitrogen Sources ◽  
Growth Patterns ◽  
Single Type ◽  
Isotopic Variation ◽  
Carbon Isotopic ◽  
Chemical Impurities ◽  
Isotopic Analyses ◽  
Δ13c Value ◽  
Reduction Of Co2

Abstract The morphological, chemical impurities and carbon isotope properties of diamonds may reveal subtle details of their mantle source and growth characteristics, supporting efforts towards identifying their original place of harvesting. Here we investigate the mantle carbon and nitrogen sources and growth patterns from selected diamonds mined from four kimberlites: macro-sized diamonds from River Ranch kimberlite in Zimbabwe and the Swartruggens and Klipspringer kimberlitic deposits from South Africa, and micro-sized diamonds from the Klipspringer and Premier kimberlite intrusions in South Africa. Type IaAB diamonds are found in all the samples; Type IaB diamonds only occur in samples from the Swartruggens, River Ranch and Premier kimberlites. A single Type II diamond (nitrogen below the detection limit) was also observed in the River Ranch and Premier kimberlites. Both the micro- and macro-sized diamonds from Klipspringer have similar nitrogen contents. Based on the % B-defect, the diamonds from Klipspringer are grouped into low- and high-nitrogen aggregates (i.e. % of B-defect <40% and >56%, respectively) that likely represent two different diamond forming episodes. Time averaged mantle storage temperatures for Type IaAB diamonds are calculated to have been: 1060°C for Swartruggens; 1190°C for River Ranch; 1100°C (low aggregated); and 1170°C (highly aggregated) for Klipspringer, and 1210°C for Premier diamonds. The CL-images of the River Ranch, Klipspringer and Premier diamonds reveal multi-oscillatory growth zones. The carbon isotopic analyses on the diamonds reveal an average δ13CVPDB value of: -4.5‰ for Swartruggens; -4.7‰ for River Ranch; -4.5‰ for Klipspringer; and -3‰ for Premier. With the exception of the diamond from Premier, the average δ13C value of the diamonds are similar to the average δ13C value of the mantle (-5‰), which is similar to the occurrence of diamonds in the other kimberlites. The internal carbon isotopic variation of individual diamonds from Swartruggens, Klipspringer and Premier are less than 4‰, which is similar to the variability of most other diamond occurrences reported from elsewhere in the world. Up to 6.7‰ internal carbon isotopic variation was observed in a single diamond from River Ranch. The internal carbon isotopic studies of the diamonds reveal that the primary carbon in the Swartruggens and Klipspringer was derived from an oxidation of CH4-bearing fluid, whereas in the River Ranch the primary carbon was derived from the reduction of carbonate-or CO2-bearing fluids. The Swartruggens diamonds also reveal a secondary carbon sourced from a reduction of CO2- or carbonate-rich fluid or melt. Diamonds from Klipspringer exhibit a cyclic change in δ13C values that reflects fluctuation in a complex mantle perturbation system or periodic change in fugacity of the mantle. Based on this study, we conclude that, in principle, a selected range of diamond signatures might be used to fingerprint their origins; especially when linked to their other physical properties such as a low temperature magnetic signature.

Sign in / Sign up

Export Citation Format

Share Document