Investigation of the production and dietary features of oyster mushrooms for a planned lunar farm.

In our previous work, we organized a project mainly to design a lunar mushroom farm. In this work, we proceeded to study the features of the production and consumption of oyster mushrooms in that project. Oyster mushrooms were grown in cultivation vessels containing a sterilized substrate. The fruit yield and mass of the spent substrate in the cultivation vessels were measured. A three-factor experiment was carried out with the subsequent application of the steep ascent method and correlation analysis in the R program. These factors included the density of the substrate in the cultivation vessel, its volume, and the number of harvesting flushes. The data obtained was used to calculate the process parameters: productivity, speed and degree of substrate decomposition, and biological efficiency. The consumption and dietary features of oyster mushrooms were modeled in Excel using the Solver Add-in. In the three-factor experiment, the highest productivity amounting to 272 g of fresh fruiting bodies/(m3*day) was obtained with a substrate density of 500 g/L, a cultivation vessel volume of 3 L, and two harvest flushes. The application of the method of steep ascent showed that it is possible to increase the productivity by increasing the substrate density and reducing the volume of the cultivation vessel. In production, there is a need to tally the substrate decomposition speed with the substrate decomposition degree and the biological efficiency of growing oyster mushrooms, since these process parameters have a negative correlation. Most of the nitrogen and phosphorus passed from the substrate into the fruiting bodies. These biogenic elements could limit the yield of oyster mushrooms. It is safe to set the daily intake of oyster mushrooms at 100-200 g while maintaining the antioxidant capacity of the food set.

The effect of supplementation of the soil-like substrate with wheat straw mineralized to different degrees on wheat productivity in closed ecosystems.

Successful incorporation of soil-like substrate (SLS) into biotechnical life support systems is often complicated by the necessity to maintain the balance between flows of mineral elements taken up from the substrate by growing plants and mineral elements added to the SLS as components of mineralized plant inedible biomass. An imbalance between these two flows can be caused by the addition of recalcitrant plant waste such as wheat straw. The purpose of this study was to determine whether the availability of essential nutrients to be taken up by the roots of the wheat plants grown on the SLS could be enhanced by supplementing the SLS with the products derived from wheat straw subjected to different levels of physicochemical mineralization in the aqueous solution of hydrogen peroxide. Different degrees of straw mineralization were achieved by using different ratios of the aqueous solution of hydrogen peroxide to straw. The study showed that supplementation of the SLS with insufficiently oxidized products of physicochemical mineralization of straw resulted in a decrease in the grain yields. The inhibitory effect of the straw subjected to physicochemical oxidation increased with a decrease in the degree to which the straw had been oxidized. Only supplementation with the straw mineralized to the highest possible degree did not inhibit plant growth and development, and the crop yield in that treatment was higher than in the other treatments.

Deep Physical-Chemical Purification of Gas Medium in Artificial Ecosystems.

The results of experiments on application of a newly developed facility for oxidation of volatile organic compounds on a platinum catalyst are presented. The feasibility of using this method in artificial ecosystems as a whole and in mass exchange of closed biological-technical life support systems in particular is shown. The possibility of deep purification of gas emitted from the reactor of physical-chemical processing of organic wastes is demonstrated. Wheat growing experiment on using the facility for oxidation of volatile organic compounds in a sealed chamber was performed. No adverse effect of probable toxic oxidation products on wheat plants during a 4-day experiment was determined.

Processing of household waste in the BTLSS using the wet combustion method.

The present study discusses physicochemical methods of organic waste processing in closed biotechnical life support systems (BTLSS). Sanitary and household cotton wastes were processed by the method of wet combustion in hydrogen peroxide using an alternating current electric field - a promising physicochemical method for organic waste processing in the BTLSS. The highest efficiency of the process (in terms of power consumption, duration of the process, and oxidation rate) was achieved in experiments with oxidation of a combination of cotton fabrics and urea-containing wastes such as human urine and feces. The reason for this must be that urea is a reactive aqueous solvent of cellulose.

Incorporation of mineralized human waste and fish waste as a source of higher plant mineral nutrition in the BTLSS mass exchange.

The present study deals with the development of the principles and conditions of fish waste mineralization using the method of wet combustion with hydrogen peroxide in alternating electromagnetic field and describes testing mineralized human waste and fish waste as sources of nutrients for plants in the biotechnical human life support system (BTLSS). The study shows that mineralization of fish waste in the wet combustion reactor should be performed in the presence of readily oxidized organic matter, represented by human waste, as an activator of oxidation. Re-mineralization of the sediment in the mixture of hydrogen peroxide and nitric acid in the wet combustion reactor converts mineral elements bound in the sediment into the form available to plants. Using mineralized fish waste as an additional source of mineral elements in the nutrient solutions for growing plants based on mineralized human waste is a way to reduce the amounts of mineral elements added to the solution to replenish it, enabling fuller closure of material loops in the BTLSS.

Feasibility of incorporating all products of human waste processing into material cycling in the BTLSS.

The present study addresses the ways to increase the closure of biotechnical life support systems (BTLSS) for space applications. A promising method of organic waste processing based on "wet combustion" in hydrogen peroxide developed at the IBP SB RAS to produce fertilizers for higher plants is discussed. The method is relatively compact, energy efficient, productive, and eco-friendly. However, about 4-6 g/L of recalcitrant sediment containing such essential nutrients as Ca, Mg, P, Fe, Cu, Mn, and Zn precipitates after the initial process. These elements are unavailable to plants grown hydroponically and, thus, drop out of the cycling as dead-end products. Possible methods of dissolving that sediment have been studied. Results of experiments show that the most promising method is additional oxidation of the sediment in HNO3 + H2O2. By using the new technological process, which only involves substances synthesized inside the BTLSS material flows, more than 90% of each nutrient can be converted into the form available to plants in irrigation solutions, thus returning them into the material cycling. The results obtained in this study show the efficacy of supplementing the irrigation solutions with the mineral nutrients after sediment dissolution. Lettuce plants grown as the test object on the newly prepared irrigation solutions produced the yield that was more than twice higher than the yield produced on the nutrient solutions prepared without the sediment conversion into a soluble form. Composition of the gases emitted during this process has been analyzed. Dynamics of oxidation of the small fractions of a wax-like sediment remaining after the initial sediment dissolution in HNO3 + H2O2 in the BTLSS soil-like substrate has been studied. The entire technological scheme aimed at the full inclusion of all human wastes into the BTLSS cycling has been suggested and discussed. A process scheme of including products of human waste processing in the biotic cycle of the BTLSS is discussed in the conclusion.

Development of human exometabolite deep mineralization method for closed ecosystems.

Methods of physicochemical further oxidation of hardly soluble sediment obtained from "wet combustion" of human exometabolites applied to space-purpose Bio Technological Life Support Systems (BTLLS) were studied. Most hardly dissoluble sediment containing Ca, P, Mg, and other essential plant nutrition elements were shown to dissolve in H2O2 and HNO3 aqueous media activated by alternating electric current. Dissolved additional mineral elements allowed (as demonstrated for lettuce) to increase the productivity of BTLLS phototrophic unit plants more than twice, which is comparable to their productivity on standard Knop solution with balanced chemical composition. Thus, dissolved mineral elements can be involved into BTLLS turnover process and increase its closure degree.

Physicochemical conversion of human exometabolites for the NaCl involvement into the mass exchange in closed life support systems.

The results of the original physicochemical method of NaCl recovery out of the mineralized human metabolites' solution obtained after their oxidation in H2O2 aqueous solution under the influence of alternating electric current are presented. The technological stages of the newly developed method are described, and its efficiency at each stage is demonstrated. The possibility to efficiency isolate Na from the NaHCO3 solution by applying electrodialysis technology and temperature separation is demonstrated. The HCl synthesis from Cl2 and H2 released during electrolysis is stable, allowing its combining with electrodialysis aimed at NaCl production under the conditions of a closed life support system.