Abstract: Hydrogen sulfide present in an aqueous system is removed and the production of hydrogen sulfide by sulfate-reducing bacteria (SRB) is eliminated by introducing into the system nitrite and nitrate and/or molybdate ions, whereby denitrifying microorganisms outcompete the sulfate-reducing bacteria for the available carbon nutrients, thus preventing the SRB from producing hydrogen sulfide and the nitrite along with the denitrifying microorganisms remove hydrogen sulfide already present in the system. The system which contains the denitrifying microorganisms and which is essentially free of hydrogen sulfide can enhance oil recovery by means of a microbial enhanced oil recovery mechanisms.

Abstract: Hydrogen sulfide present in an aqueous system is removed and the production of hydrogen sulfide by sulfate-reducing bacteria (SRB) is eliminated by introducing into the system nitrite and nitrate and/or molybdate ions, whereby denitrifying microorganisms outcompete the sulfate-reducing bacteria for the available carbon nutrients, thus preventing the SRB from producing hydrogen sulfide and the nitrite along with the denitrifying microorganisms remove hydrogen sulfide already present in the system. The system which contains the denitrifying microorganisms and which is essentially free of hydrogen sulfide can enhance oil recovery by means of a microbial enhanced oil recovery mechanisms.

Abstract: A method of releasing metals from catalysts in a form that is readily recoverable using denitrifying bacteria is disclosed. The method can be used to regenerate catalysts and to recover metals from catalysts, especially molybdenum and nickel.

Abstract: A novel strain of P. pastoris and an alcohol oxidase free of catalase activity produced therefrom is provided.

Abstract: A method of microbial enhanced oil recovery includes introducing, into an underground carbonate-containing rock formation that defines an anaerobic environment, denitrifying microorganisms, water, and a source of nitrate ion. The microorganisms reduce the nitrate and produce sulfuric acid which dissolves the rock formation, releasing oil. The microorganisms can be denitrifying Thiobacilli, such as T. denitrificans.

Abstract: Process for transforming yeast strains of the genus Pichia is disclosed. Novel yeast strains of the genus Pichia which can be transformed with recombinant DNA material are also disclosed. In addition, a method for isolating functional genes and other functional DNA sequences from yeast strains of the genus Pichia is described.

Abstract: Novel DNA sequences which code for the production of the Pichia protein argininosuccinate lyase are provided. Novel constructs including these sequences, as well as organisms transformed therewith are provided. In addition, novel strains of Pichia defective in argninosuccinate lyase activity are also provided.

Abstract: Single cell protein (SCP) is produced at high yields from a novel methanol assimilating Methylomonas sp. grown at elevated temperatures in an aerobic bacterial fermentation process.