Production of extracellular aspartic protease in submerged fermentation with Mucor mucedo DSM 809

Fungal milk-clotting enzymes have gained value as bovine Chymosin substitutes in the cheese industry. In this work, the effects of culture conditions on the production of extracellular milk clotting enzymes from Mucor mucedo DSM 809 in submerged fermentation were studied. The maximum activity was observed after 48 h of cultivation at 24°C in Erlenmeyer flasks. The optimized initial pH and shaking speed for enzyme production were 4.5 and 220 rpm, respectively. Glucose at a concentration of 1% (w/v) was the best carbon source for the production of enzyme among the carbohydrates examined (glucose, fructose, lactose, maltodextrin). On the other hand casein at a concentration of 0.5% (w/v) was the selected nitrogen source in the media formulation. Under optimized conditions enzyme levels reached 130 SU per ml fermentation broth. The inoculum type and size has also affected biomass production and the biosynthesis of the enzyme. The preferred method was the inoculation of the culture media with spores at a total load of 6x105 spores per flask.Key words: Milk clotting enzyme, Aspartic protease, Mucor mucedo, Sub-merged fermentation

Cor triatriatum sinister: two cases diagnosed in adulthood and a review of literature

Cor triatriatum sinister is a rare condition caused by a membrane within left atrium that separates pulmonary veins from mitral valve (10). While the condition is usually diagnosed at childhood, rare presentation during adulthood is observed when the membrane is incomplete. We report two cases of incomplete cor triatriatum sinister diagnosed during adulthood and review literature for this rare anomaly

Production of lactic acid from beet molasses by calcium alginate immobilized Lactobacillus delbrueckii IFO 3202

WOS: 000078820500005Lactic acid was produced from pretreated beet molasses by the homofermentative organism Lactobacillus delbrueckii subsp delbrueckii IFO 3202 entrapped in calcium alginate gel using batch, repeated batch and continuous fermentation systems. In batch fermentation studies successful results were obtained with 2.0-2.4 mm diameter beads prepared from 2% sodium alginate solution. The highest effective yield (82.0%) and conversion yield (90.0%) were obtained from substrate concentrations of 52.1 and 78.2 g dm(-3) respectively. The gel beads produced lactic acid for 14 consecutive batch fermentations without marked activity loss and deformation. In the continuous fermentation, the highest lactic acid (4.22%) was obtained at a dilution rate of 0.1 h(-1) while the highest productivity (13.92 g dm(-3) h(-1)) was obtained at a dilution rate of 0.4 h(-1). (C) 1999 Society of Chemical Industry

Optimal Coordination of Directional Overcurrent Relays Using Artificial Ecosystem-Based Optimization

Optimal directional overcurrent relays (DOCRs) coordination aims to find the optimal relay settings in order to protect the system, where, the primary relays are operated in the first to clear the faults, then the corresponding backup relays should be operated in case of failing the primary relays. DOCRs coordination problem is a non-convex and high dimensional optimization problem and it should be solved subject to operating constraints. The objective function for optimal coordination of DOCRs aims to minimize total operation time for all primary relays without violation in constraints to maintain reliability and security of the electric power system. This paper proposes the artificial ecosystem-based optimization (AEO) algorithm is for the solution of the DOCRs coordination problem. Simulation studies were carried out in IEEE 3-bus and IEEE 4-bus test systems to evaluate the performance of the proposed algorithm. The simulation results are compared with differential evolution algorithm (DE), opposition based chaotic differential evolution algorithm (OCDE1and OCDE2), and three real coded genetic algorithms (RCGAs) namely: Laplace crossover power mutation (LX-PM), Laplace crossover polynomial mutation (LX-POL), bounded exponential crossover power mutation (BEX-PM). The results clearly showed that the proposed algorithm is a powerful and effective method to solve the DOCRs coordination problem. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG

Effects of operational parameters and ultrasonic pretreatment on supercritical CO2 extraction of diesel fuel from soil

Supercritical fluid extraction (SFE) using CO2 was performed on soil material artificially contaminated with diesel fuel. Raising the temperature from 313 K to 343 K caused the recovery efficiency to increase from 52 to 76%. Pressure and CO2 flow rate were found to be less important. As expected, increasing extraction time resulted in higher recoveries. Ultrasonic pretreatment of the soil material was found to be very effective, possibly due to disrupting the strong interaction bonding between soil matrix and contamination

Adsorption Equilibrium and Dynamics of Lactase/Cm-Sephadex System

WOS: A1995RQ91000009Partitioning behaviour and adsorption isotherms of lactase/CM-Sephadex system at equilibrium were investigated together with the adsorption kinetics in this study. Maximum adsorption was obtained at the pH values between 5.5-6.0. Adsorption isotherm was a close fit to the Langmuir model

Optimal Power Flow Using Manta Ray Foraging Optimization

The optimal power flow (OPF) stands for the problem of specifying the best-operating levels for electric power plants in order to meet demands given throughout a transmission network, usually with the objective of minimizing operating cost. Recently, the OPF has become one of the most important problems for the economic operation of modern electrical power plants. The OPF problem is a non-convex, high-dimensional optimization problem, and powerful metaheuristic optimization algorithms are needed to solve it. In this paper, manta ray foraging optimization (MRFO) was used to solve the OPF problem which takes into account the prohibited operating zones (POZs). The performance of the MRFO was tested on IEEE 30-bus test system. The results obtained from the simulations were compared with well-known optimization algorithms in the literature. The comparative results showed that the MRFO method ensures high-quality solutions for the OPF problem. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG

An endo-beta-1,4-xylanase from Rhizopus oryzae: production, partial purification and biochemical characterization

An endoxylanase (1,4-beta -D-xylan xylanohydrolase, EC 3.2.1.8) was produced by Rhizopus oryzae fermentation. Different xylan-containing agricultural byproducts such as wheat straw, wheat stems, cotton bagasse, hazelnut shells, corn cobs and oat sawdust were used as the carbon source, white soybean bagasse was used as both the nitrogen and carbon source in the enzyme production medium. Partial steam hydrolysis of the agricultural byproducts increased the enzyme yield of the microorganism, The highest xylanase activity, 260 IU/ml fermentation medium, was obtained by using a medium containing 3% hydrolyzed com cobs, 1% hydrolyzed soybean bagasse, 1% ammonium sulfate and 0.5% sodium chloride at 35 degreesC, pH 5, 350 rpm and under aerobic conditions in a 2-1 fermenter. A maximal cellulose activity of 0.06 IU/ml was observed. The enzyme was partially purified from the culture medium by ammonium sulfate precipitation and cation exchange filtration. A 55-fold purification was achieved, with the purified xylanase having a specific activity of about 50 IU/mg protein. The molecular weight of the enzyme is about 22 kDa by SDS-PAGE. The optimal pH and temperature values of the enzyme were about 4.5 and 55 degreesC, respectively. The enzyme obeys Michaelis-Menten kinetics with Km and V. values being 18.5 mg xylan/ml and 90 IU/mg protein, respectively. (C) 2001 Elsevier Science Inc. All rights reserved