Search

The experiment was based on filtration of the highly aggressive water through the melaphyre bed. The quartz bed was non-reactive reference material. The aim of this work was to determine the ability of the melaphyre to remove aggressive CO2 during the chemical reaction. It was noted that a decrease of acidity of the filtrate in comparison to the feed and an increase of its alkalinity and pH. It was calculated that until the moment of exhaustion of the de-acidifying properties of the melaphyre, maximum amount of bound CO2 added to the water was 29.7 g CO2/L of the bed, and maximum amount of the aggressive CO2 removed from the water was 33.3 g CO2/L of the bed. Regarding very high content of the aggressive CO2 (116 mg/L average) in the feed only 28.76% of this component was subject to transformation into bound and affiliated CO2 in the filtrate. For the melaphyre bed the CO2 loss from the experiment system following from desorption was 7.80% of the total load of CO2 added with the feed. On the quartz bed the loss was slightly lower 4.56%.

Background: Rhodotorula glutinis yeast is capable of the synthesis of numerous valuable metabolites with extensive potential industrial usage. This paper reports the study on determination of the effect of initial culture medium pH on growth and protein, lipid and carotenoid biosynthesis by R. glutinis yeast. Results: The highest biomass yield was obtained in media at pH 4.0-7.0, and the value after 72 h was 17.2-19.4 g d.w. /L. An initial pH of the medium in the range 4.0-7.0 have no significant effect on the protein (38.5-41.3 g/100 g d.w. ), lipid (10.2-12.7 g/100 g d.w. ), or carotenoid (191.7-202.9 μg/g d.w. ) content in the biomass, or on the profile of synthesized fatty acids and carotenoids. The whole pool of fatty acids was dominated by oleic (48.1-53.4%), linoleic (21.4-25.1%) and palmitic acids (13.0-15.8%). In these conditions, the yeast mainly synthesized torulene (43.5-47.7%) and β-carotene (34.7-38.6%), whereas the torularhodin contribution was only 12.1-16.8%. Cultivation in medium at initial pH of 3.0 resulted in a growth reduction (13.0 g d.w. /L) and total carotenoid (115.8 µg/g d.w. ), linoleic acid (11.5%) and torularhodin (4.5%) biosynthesis. Conclusion: The different values of initial pH of the culture medium with glycerol and deproteinized potato wastewater had a significant effect on the growth and on protein, lipid and carotenoid biosynthesis by R. glutinis yeast. Normal 0 false false false EN-GB X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

In this study, we aimed to determine the effect of exogenous stress factors (sodium chloride as osmotic stressor, hydrogen peroxide as an inducer of oxidative stress, white light irradiation, and low temperature) on the biosynthesis of carotenoids and lipids by red yeast (Rhodotorula glutinis, R. mucilaginosa, and R. gracilis) during cultivation in media containing potato wastewater and glycerol. According to our results, the yeast were able to grow and biosynthesize lipids and carotenoids in the presence of the applied stress factors. Low temperature caused an increase in the biosynthesis of intracellular lipids and carotenoids. R. gracilis synthesized lipids (21.1 g/100 gd.w.) and carotenoids (360.4 µg/gd.w.) in greater quantities than that of other strains. Under these conditions, there was also an increase in the content of unsaturated fatty acids, especially linoleic and linolenic acids. The highest percentage of polyunsaturated fatty acid (PUFA) (30.4%) was synthesized by the R. gracilis yeast after cultivation at 20°C. Their quantity was 2.5-fold greater than that of the biomass grown in control conditions. The contribution of individual carotenoid fractions depended both on the yeast strain and the culture conditions. Induction of osmotic stress and low temperature intensified the biosynthesis of β-carotene (up to 73.9% of the total carotenoid content). In oxidative stress conditions, yeast synthesized torulene (up to 82.2%) more efficiently than under other conditions, whereas white light irradiation increased the production of torularhodin (up to 20.0%).

A high concentration of aggressive carbon dioxide disturbs many technological processes in water treatment. It also causes the development of corrosion in steel and concrete. De-acidification of groundwater by means of air bubbles alters pH and the concentration of aggressive carbon dioxide. This was investigated for the variables of air flow (Q = 20–50 L h−1) and height of water layer (H = 25–75 cm) as well as aeration time (t = 0–20 min). The obtained three-parameter models showed good correlation with the experimental results, except in a few cases where r2 was bigger than 0.9. Furthermore, they allow for prediction of an increase of pH and a decrease in concentration of aggressive carbon dioxide in aerated water. The effectiveness of de-acidification of groundwater was evaluated using indices of water stability (Langelier Saturation Index, Precipitation Index, Ryznar Stability Index, Aggressiveness Index and Index of Aggressiveness). Although as a result of aeration an increase of pH over 7 was observed, the non-corrosive values of the indices were not reached. This was due to a very low alkalinity of water, which was 0.7 meq L−1.

Yeast cell wall β-glucans exhibit valuable functional properties, including therapeutic ones. The possibility of using deproteinated potato juice water (DPJW) with the addition of glycerol in yeast culture of Candida utilis ATCC 9950 for biosynthesis of β(1,3)/(1,6)-glucans of cell wall was determined. The biosynthesis of β-glucans was preferably intensified by media prepared from DPJW at pH 5.0 with 5 or 10 % addition of glycerol. Cells from these cultures were characterized and found to possess thickest cell walls and β-glucan layers. The content of β-glucans in the walls’ preparations was estimated to be approximately 44–45 % and was significantly higher in comparison with the content after culturing in synthetic YPD medium (approximately 31 %). The new developed media may be used in the production of C. utilis biomass with enhanced content of functional β-glucans. It creates the possibility of a favorable, simultaneous management of waste potato juice water and glycerol in the formation of β(1,3)/(1,6)-glucans.