The disclosure discloses a mutant of nitrile hydratase derived from Caldalkalibacillus thermarum, and belongs to the technical field of enzyme engineering. The nitrile hydratase mutant Cal. t Nhase-A20V provided by the disclosure has a half-life of about 10 min at 70? C., which does not change much compared with the thermal stability of the wild enzyme. The specific enzyme activity of the mutant Cal. t Nhase-A20V is 128% of that of the wild enzyme. At the same time, the mutant also has better tolerance to a substrate and a product, and the final yield of nicotinamide produced by whole-cell catalysis reaches 598 g/L. Therefore, the nitrile hydratase mutant Cal. t Nhase-A20V provided by the disclosure has good enzymatic properties and is beneficial to future industrial production.

Provided is an improved nitrile hydratase with improved catalytic activity. Also provided are DNA for coding the improved nitrile hydratase, a recombinant vector that contains the DNA, a transformant that contains the recombinant vector, nitrile hydratase acquired from a culture of the transformant, and a method for producing the nitrile hydratase. Also provided is a method for producing an amide compound that uses the culture or a processed product of the culture. The improved nitrile hydratase contains an amino acid sequence represented by SEQ ID NO: 50 (GX.sub.1X.sub.2X.sub.3X.sub.4DX.sub.5X.sub.6R) in a beta subunit, and is characterized in that X.sub.4 is an amino acid selected from a group comprising cysteine, aspartic acid, glutamic acid, histidine, isoleucine, lysine, methionine, asparagine, proline, glutamine, serine and threonine.

Provided are methods and compositions for inhibiting or reducing fungal growth. The methods comprise exposing a location to a composition comprising one or more enzymes, one or more bacteria, and/or an enzymatic extract, wherein the one or more enzymes, one or more bacteria, and/or the enzymatic extract isolated from one or more bacteria are exposed to location in a quantity sufficient to inhibit or reduce fungal growth.

The present invention provides a fused NHase with improved specific activity and stability, which relates to the field of genetic engineering. This invention provides a method of overexpressing a fused NHase in E. coli and producing a mutant NHase with improved stability and product tolerance. The invention provides a simple, efficient and safe method of making mutant NHase, and can produce a large amount of soluble NHases in a short period. The present invention makes a contribution to large-scale industrial production and further theoretical study of NHases.

The present invention provides a fused NHase with improved specific activity and stability, which relates to the field of genetic engineering. This invention provides a method of overexpressing a fused NHase in E. coli and producing a mutant NHase with improved the stability and product tolerance. The invention provides a simple, efficient and safe method of making mutant NHase, and can produce a large amount of soluble NHases in a short period. The present invention makes a contribution to large-scale industrial production and further theoretical study of NHases.

Hopanoids, hopanoids-producing nitrogen-fixing bacteria, and related formulations, systems and methods are described herein. In particular, hopanoids alone or in combination with hopanoid-producing nitrogen-fixing bacteria can be used as biofertilizer to stimulate plant growth and yield with enhanced tolerance to diverse stresses found in plant-microbe symbiotic microenvironments.

The invention relates to a bacterial strain belonging to the genus Rhodococcus which is a producer of a nitrile hydratase. The invention also relates to a method for producing acrylamide by hydration of acrylonitrile using a biomass of the bacterial strain and to a method of culturing the bacterial strain.

The invention relates to a process for producing an aqueous acrylamide solution, comprising: (a) combining water and at least one biocatalyst having nitrile hydratase activity to provide a slurry; (b) feeding acrylonitrile into a reactor comprising said slurry to provide a reaction mixture; and (c) monitoring said reaction mixture by online GC to measure a concentration of acrylonitrile in reactor's headspace with several detection technologies selected in the group consisting of Flame Ionization Detector, Mass Spectrometry, Thermal Conductivity Detector, Electron Capture Detector, Nitrogen-Phosphorus detector and vacuum ultraviolet detector.

The present invention relates to a variant nitrile hydratase which is engineered to comprise greater activity and/or stability, nucleic acids encoding said nitrile hydratase, and microbia engineered to express said novel nitrile hydratase. Additionally the invention relates to the use of this nitrile hydratase and microbia which express said nitrile hydratase as a biocatalyst, particularly in methods for producing an amide compound from a nitrile compound, preferably for use in converting acrylonitrile to acrylamide.

A method for producing an amide compound from a nitrile compound in the presence of a biocatalyst having nitrile hydratase activity includes, at least in the presence of air, when a liquid composition of a reaction solution is such that a concentration of the nitrile compound in a gas phase portion of a reactor containing the reaction solution is in an explosion range, performing a hydration reaction under a condition that an oxygen concentration of the gas phase portion of the reactor is 10% by volume or less. The nitrile compound is, for example, preferably acrylonitrile or methacrylonitrile.