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 g_d.w.) and carotenoids (360.4 µg/g_d.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%).

Background: Rhodotorula glutinis is capable of synthesizing numerous valuable metabolites with extensive potential industrial usage. This paper reports the effect of initial culture medium pH on growth and protein, lipid, and carotenoid biosynthesis by R. glutinis. Results: The highest biomass yield was obtained in media with pH 4.0–7.0, and the value after 72 h was 17.2–19.4 gd.w./L. An initial pH of the medium in the range of 4.0–7.0 has no significant effect on the protein (38.5–41.3 g/100 gd.w.), lipid (10.2–12.7 g/100 gd.w.), or carotenoid (191.7–202.9 μg/gd.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 contribution of torularhodin was only 12.1–16.8%. Cultivation in medium with initial pH 3.0 resulted in a reduction in growth (13.0 gd.w./L) and total carotenoid (115.8 μg/gd.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 protein, lipid, and carotenoid biosynthesis by R. glutinis

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.

For groundwater treatment, the technologies involving oxidation on MnO_x filter bed are beneficial, common, and effectively used. The presence of MnO_x is the mutual feature of filter media, both MnO_x-coated mineral materials like quartz sand and gravel, chalcedonite, diatomite, glauconite, zeolite, or anthracite along with consisting of MnO_x manganese ores. This review is based on the analysis of research and review papers, commercial data sheets, and standards. The paper aimed to provide new suggestions and useful information for further investigation of MnO_x filter media for groundwater treatment. The presented compilations are based on the characteristics of coatings, methods, and conditions of its obtaining and type of filter media. The relationship between the properties of MnO_x amendments and the obtained purification effects as well as the commonly used commercial products, their features, and applications have been discussed. The paper concludes by mentioning about improving catalytic/adsorption properties of non-reactive siliceous media opposed to ion-exchange minerals and about possible significance of birnessite type manganese oxide for water treatment. Research needs related to the assessment of the use MnO_x filter media to heavy metals removal from groundwater in field operations and to standardize methodology of testing MnO_x filter media for water treatment were identified.

The study aimed to determine the nature of the kinetics of the manganese sorption process on Ukrainian tuff and basalt at different temperatures characteristic of the natural water environment. The scope of the research included manganese sorption kinetic test on natural mineral sorbents at temperatures of 10, 17.5 and 25 °C in slightly acidic conditions. Sorption (pseudo-first order, pseudo-second order and Elovich models) and diffusion kinetic models (liquid film diffusion and intraparticle diffusion) were used in the analysis of test results. The manganese sorption process on both tuff and basalt proceeded quickly. The dynamic equilibrium state of manganese sorption settled after 35 and 45 min on tuff and basalt respectively. Although the process took place in a slightly acidic environment and below pH_PZC of the sorbents, possible electrostatic repulsion did not inhibit the removal of Mn. The Mn sorption on both materials followed the PSO kinetics model. Based on the diffusion kinetic models, it was determined that Mn sorption process on both materials was influenced by diffusion through the boundary layer and intraparticle diffusion. The differences in removal efficiency and rate of Mn sorption in the temperature range of 10–25 °C were not found.

A process based on pre-treatment and membrane desalination was studied for the treatment of the flowback water from drilling for shale gas in Lubocino in Poland. The effectiveness of pre-treatment technology, which contained NaOH alkalization, KMnO₄ oxidation, filtration, sorption, and fine filtration, was studied. Also the usefulness of nanofiltration (NF) and reverse osmosis (RO) membranes for flowback desalination was tested. The study was carried out in the semi-pilot scale. The applied pre-treatment technology made possible to obtain a product that can be placed on the NF and RO elements (turbidity = 0.882 NTU, silt density index = 3.1). The 4040-SR100-N2 NF element was ineffective for flowback water purification, and the retention of contaminants was low (5.1% conductivity, 18.2% total hardness, 9.2% TOC). The AG4040FM RO element was characterized by higher retention (conductivity 93.9%, total hardness 98.3%, TOC 78.1%), but low volume concentration ratio (VCR) (VCR = 1.6) with more than 50% decrease in the permeate flux obtained. The AD-90 RO element was characterized by the highest retention (conductivity 99.3%, total hardness 99.8%, TOC 91.1%), and VCR was 4 by minimal decrease of permeate flux. Proposed pre-treatment technology combined with desalination on AD-90 RO element allows to obtain flowback water reusage. The return of flowback water to the environment requires the application of advanced oxidation to decrease the level of organic contamination.