A Simple and Efficient Mechanical Cell Disruption Method Using Glass Beads to Extract β-Glucans from Spent Brewer’s Yeast

β-glucan extraction from spent brewer’s yeast is a long process that starts with the lysis of yeast cells, this step lasting up to 36 h and can be disadvantageous when working on a small scale. In this study, a rapid cell rupture method was selected for the lysis of spent brewer’s yeast to obtain β-glucans. Optimal parameters were determined for the lysis of a cellular suspension of spent brewer’s yeast by vortexing with glass beads. Thus, parameters such as the number of 10 min vortex cycles from 1 to 3, the concentration of cell suspension (5, 10, and 15%), and the ratio of yeast/glass beads (1:1, 1:2, and 1:3) were varied in a Box-Behnken design. A cell lysis mechanism using glass beads allows the cell to rupture and permits the removal of intracellular content. An increase in yeast suspension concentration decreased the disruption efficiency, while a proportional increase was observed with the yeast/glass beads ratio and the increasing number of vortexing cycles. The optimal parameters for cell lysis were found to be a cell suspension concentration of 5%, a ratio of yeast/glass beads of 1:2, and a vortexing cycle of 3, with a disruption efficiency of 99.8%. The β-glucan fraction extracted from the optimal sample showed characteristic absorption bands at 1370.77 and 1153.92 cm−1, the content of β-glucan being 78.53%.

Suspended sediment in lowland rivers – towards identifying the ratios of mineral and organic components and their variation during the year

Concentrations of suspended sediment transported by rivers are influenced by interactions between multiple drivers that act on a range of spatial and temporal scales. Such levels vary over the year, as well as across multi-year periods. Most conventional approaches to determining suspended load are based upon analyses of total suspended sediment concentration (SSC), i.e., the sum of mineral and organic matter. This approach makes it difficult, if not impossible, to determine the impact of multiple environmental factors on changes in suspension concentration precisely. The present paper focuses on the mineral and organic components of suspended sediment with the aim of determining how our knowledge of the share of each individual component can improve interpretations of SSC fluctuations during a hydro-logical year. The analysis conducted (personal and other researchers’ results) has shown that mineral and organic suspensions demonstrate mutually incompatible opposite trends under influence of environmental factors. This analysis of organic components identifies clear seasonal trends, which indicates that organic suspensions of autogenous origin have a strong influence on the dynamics of changes in suspension concentration; such analyses are rarely included in assessments of SSC dynamics.

Differentiation of valuable for breeding sunflower lines by resistance to Phoma rot

The purpose of the research is differentiation of valuable for breeding sunflower lines by resistance to Phoma rot. The promising constant sunflower lines were estimated by their resistance to Phoma rot using methods of artificial inoculation in the greenhouse and laboratory conditions. In greenhouse conditions, there were used two methods of artificial inoculation with a fungus Plenodomus lindquistii in the bottom of leaf petiole of a sunflower plant at a stage of the first true leaf pair. Application of the pieces of agar nutrient medium with mycelium, pycnidia and picnospores (unbroken) allowed to identify resistant and mid-resistant sunflower lines (VK 900, L 86 and L 107, L 132). At inoculation with 0.2 ml of a fungus spore suspension (concentration of 1 × 106 spores/ml), five susceptible and one very susceptible sunflower lines (L 2385, L 103, L 136, L 131, L 128, and L 82) were determined. In laboratory conditions, the quick test for estimation of susceptibility to Phoma rot (dose of infection – 12 g) allowed to reveal more than 50 % of plants with healthy root system and two constant sunflower lines L 116 and L 136 with the affection degree of one point. Estimation of susceptibility to Phoma rot infection of the different organs (stem and root system) at artificial inoculation showed a possibility to differentiate sunflower lines by resistance of roots and stems and to select the most promising for the further work in breeding.

Experimental Study on the Suspension Amount of Invasion Gas in Drilling Fluid with Yield Stress

The gas suspension phenomenon caused by the yield stress of the drilling fluid affects the accurate calculation of wellbore pressure after gas invasion. At present, most studies on the bubble suspension in the yield stress fluid focus on the single-bubble suspension condition and there are few studies on the gas suspension concentration. This paper carried out the GSC (gas suspension concentration) experiment in the simulated drilling fluid, xanthan solution, with different gas invasion methods. The GSC in the drilling fluid under the conditions of diffuse gas invasion and differential pressure gas invasion was simulated by using two methods of stir-depressurization and continuous ventilation. The results showed that when the size of a single bubble satisfied the single-bubble suspension condition, multiple bubbles can be suspended at the same time. The GSC is affected by the average size of the suspended bubbles, the yield stress of the drilling fluid, and the gas invasion modes. For different gas invasion modes, the empirical models of critical GSC related to the dimensionless number Bi are established. Compared with the experimental data, the relative error of the critical GSC in diffuse gas invasion is less than 6% and the relative error of the critical GSC in differential pressure gas invasion is less than 10%. The results of this work can provide guiding significance for accurate calculation of wellbore pressure.

A Wellbore Pressure Calculation Method Considering Gas Suspension in Wellbore Shut-In Condition

In the oil industry, the drilling fluid is yield stress fluid. The gas invading the wellbore during the drilling process is distributed in the wellbore in the form of bubbles. When the buoyancy of the bubble is less than the resistance of the yield stress, the bubble will be suspended in the drilling fluid, which will lead to wellbore pressure inaccurately predicting and overflow. In this paper, the prediction model of gas limit suspension concentration under different yield stresses of drilling fluids is obtained by experiments, and the calculation method of wellbore pressure considering the influence of gas suspension under shut-in conditions is established. Based on the calculation of the basic data of a case well, the distribution of gas in different yield stress drilling fluids and the influence of gas suspension on the wellbore pressure are analyzed. The results show that with the increase of yield stress, the volume of suspended single bubbles increases, the gas suspension concentration increases, and the height at which the gas can rise is reduced. When the yield stress of drilling fluid is 2 Pa, the increment of wellhead pressure decreases by 37.1% compared with that without considering gas suspension, and when the yield stress of drilling fluid is 10Pa, the increment of wellhead pressure can decrease by 78.6%, which shows that when the yield stress of drilling fluid is different, the final stable wellhead pressure is quite different. This is of great significance for the optimization design of field overflow and kill parameters, and for the accurate calculation of wellbore pressure by considering the suspension effect of drilling fluid on the invasion gas through the shut in wellhead pressure.

A bending fluctuation-based mechanism for particle detection by ciliated structures

To mimic the mechanical response of passive biological cilia in complex fluids, we study the bending dynamics of an anchored elastic fiber submitted to a dilute granular suspension under shear. We show that the bending fluctuations of the fiber accurately encode minute variations of the granular suspension concentration. Indeed, besides the stationary bending induced by the continuous phase flow, the passage of each single particle induces an additional deflection. We demonstrate that the dominant particle/fiber interaction arises from contacts of the particles with the fiber, and we propose a simple elastohydrodynamics model to predict their amplitude. Our results provide a mechanistic and statistical framework to describe particle detection by biological ciliated systems.

Penyisihan Polutan pada Palm Oil Mill Effluent (POME) Menggunakan Konsorsium Mikroalga-Bakteri dengan Sistem High Rate Algae Reactor (HRAR)

Palm oil mills in addition to producing crude palm oil also produce by-products in the form of Palm Oil Mill Effluent (POME). POME contains high amounts of organic ingredients and pollutants. One method that can be applied to treat POME is the High Rate Algae Reactor (HRAR) System. The HRAR system uses microalgae-bacterial consortium that has better performance in removing pollutants in POME and increasing the growth of microorganisms. This research aim by determining the effect of microalgae suspension concentration in the HRAR system towards the removal efficiency of Chemical Oxygen Demand (COD) and total nitrogen. The research was conducted in batch in the HRAR system that equipped with a paddle wheel, by variations of microalgae suspension concentration as 0; 10; 15; 20; and 25 (% v/v). The research was carried out for 7 days and used the sun as a source of light. Based on the research results, 25% of microalgae suspension concentration has the highest microalgae cell density, was 6,34 x 106 cells/mL and showed the best removal efficiency of COD and total nitrogen, were 78.79% and 80.37%.

Regenerative ability of grape cuttings under the influence of yeast suspension treatment

The paper presents the growing experiment results on activating the regenerative ability of Moldova table variety grape cuttings by processing pressed baking yeast suspension. The present circumstance became the basis for conducting special studies to check cutting response to the treatment with baking yeast suspension, with the identification of drug optimal concentration. In spring, the two-eyed cuttings were completely soaked for 24 hours in water, and then they were placed with the basal ends in yeast suspension at various concentrations for the same time. Moreover, these yeast suspension concentrations were tested both in pure form and in combination with 3% sucrose. As a result of the conducted studies, it was revealed that pressed baking yeast suspension at certain concentration can have an activating effect on regenerative ability of grape cuttings. The use of yeast suspension together with sucrose solution increases their physiological activity. It was found that cuttings basal end soaking in yeast suspension at concentrations of 10-20 g/l, together with sucrose, contributed to rooting increased by 20-30%, the proportion of cuttings with three roots or more – by 22.5-30.0%, the number of roots by 13.5–16.2%. The best option was with a yeast suspension concentration of 20 g/l.