Abstract: Systems and methods for packing solutions for oxygen-sensitive articles such as food, beverages, and pharmaceuticals, as well as biological samples and/or cultures are disclosed. In preferred systems and methods, oxygen is removed using a bi-enzymatic reaction sequence that recycles and depletes oxygen to extinction, preferably using an oxidase and a catalase as catalysts and a carbohydrate as co-substrate while at least one the enzymes is in a hydrogel or other polymeric formulation.

Abstract: Systems and methods for oxygen removal from aqueous solutions are presented in which a bi-enzymatic reaction sequence recycles and depletes oxygen to extinction, preferably using an oxidase and a catalase as biocatalysts and a carbohydrate as co-substrate. Contemplated systems and methods are particularly advantageous in conjunction with electrochemical reaction systems in which oxygen would adversely interfere with the reaction system.

Abstract: Systems and methods for oxygen removal from aqueous solutions are presented in which a bi-enzymatic reaction sequence recycles and depletes oxygen to extinction, preferably using an oxidase and a catalase as biocatalysts and a carbohydrate as co-substrate. Contemplated systems and methods are particularly advantageous in conjunction with electrochemical reaction systems in which oxygen would adversely interfere with the reaction system.

Abstract: The invention provides modification to the polynucleotide coding sequence for Pichia angusta NAD (P)H: nitrate reductase [YNaR1; GenBank accession number Z49110], which has Enzyme Commission number 1.7.1.2 (formerly EC 1.6.6.2), yielding the polynucleotide coding sequence for simplified eukaryotic nitrate reductase (S-NaR1). The invention also provides a method for recombinant expression of said polynucleotide code in the cells of the methylotrophic yeast Pichia pastoris to produce the polypeptide for S-NaR1, which binds the host-produced molybdenum-molybdopterin cofactor and intracellularly forms catalytically active, nitrate-reducing enzyme as small and stable multimeric proteins. The invention also provides a method for rapid and high-yielding purification of S-NaR1 by utilizing the hexa-histidine sequence at the carboxyl-terminus of said polypeptide for immobilized metal affinity chromatography.