Optimal conditions of spray drying of a fructooligosaccharide-rich mixture prepared by enzymatic conversion of sucrose were investigated. It was found that efficient drying of the mixture containing about 40 % of monosaccharides and sucrose required addition of a compound with a high glass transition temperature. The addition of maltodextrin helped to achieve satisfactory solids yield and moisture. Optimized process parameters were the feed flow rate and solids concentration, drying air flow rate and inlet temperature.
The influence of ionic strength on the adsorption capacity of seven commercial adsorbents used in downstream processing of monoclonal antibodies was examined. Affinity (MabSelect, Poros 50A High Capacity, ProSep-vA High Capacity), hydrophobic charge-induction (MEP HyperCel), and cation exchange adsorbents (FractoGel EMD SE Hicap (M), SP Sepharose Fast Flow, Ceramic HyperD F) were used to study the adsorption of polyclonal human immunoglobulin G at optimal pH values. The ionic strength, adjusted by sodium chloride concentrations in the range of 0–225 mM, strongly decreased the adsorption capacity of the cation exchangers. Equilibrium data were described in the form of the dependence of the ratio of protein concentrations in the solid and liquid phases on the total concentration of cation counter ions. They were successfully fitted and interpreted through a stoichiometric ion-exchange model.
We consider nonlinear stochastic wave equations driven by time-space white noise. The existence of solutions is proved by the method of successive approximations. Next we apply Newton’s method. The main result concerning its first-order convergence is based on Cairoli’s maximal inequalities for two-parameter martingales. Moreover, a second-order convergence in a probabilistic sense is demonstrated.