Abstract: An L-threonine-producing Escherichia coli strain and a method for producing the same are provided. The Escherchia coli strain contains chromosomal DNA with inactivated metJ gene. Therefore, expression repression of threonine biosynthesis genes by a metJ gene product is prevented, thereby producing a high concentration of threonine. Further, a high concentration of L-threonine can be produced in high yield using the method.

Abstract: An ESC (Electrostatic Chuck) to chuck an object by electrostatic force, having an ESC main body supporting the object; a guide ring supported by the ESC main body and encircling the object; a dielectric material layer interposed between the guide ring and the ESC main body; a media gas supplier to supply a media gas to the guide ring; and a power supplier to supply power to the ESC main body. With this configuration, the ESC provides an apparatus to chuck a guide ring to an ESC main body, while maintaining the guide ring and an object, such as a wafer, at the same or similar temperature, thereby enhancing uniformity of the object during a semiconductor manufacturing process such as etching, deposition, or the like.

Abstract: An electrostatic chuck (ESC) for a wafer which directs a cooling gas to predetermined cooling areas of the wafer mounted on the chuck. Ring type sealing members divide the mounted wafer into the predetermined cooling areas and the predetermined cooling areas are independently supplied with a helium cooling gas. Each of the predetermined cooling areas is supplied through a separate conduit system wherein each conduit system has a single inlet into the chuck and a plurality of outlets which emit the helium gas into a respective one of the predetermined cooling areas. The plurality of outlets for each predetermined cooling area may communicate with the inlet via a respective plurality of branch conduits or via one or more branch conduits and a peripheral conduit which connects the plurality of outlets. By independently controlling the predetermined cooling areas, temperature variations on the wafer are effectively controlled.

Abstract: The present invention provide a microorganism comprising an inactivated chromosomal tdcBC gene and an inactivated chromosomal pckA gene, which has remarkably improved productivity of L-threonine. Also, the present invention provides a method of producing L-threonine using the microorganism. The microorganism is prepared by incorporating by a recombination technique an antibiotic resistance gene into a pckA gene on the chromosome of a bacterial strain containing an L-threonine degradation-associated operon gene, tdcBC, which is inactivated. The microorganism has the effect of preventing degradation and intracellular influx of L-threonine due to the inactivation of the tdcBC operon gene, and includes more activated pathways for L-threonine biosynthesis. Therefore, the microorganism is useful for mass production of L-threonine because of being capable of producing L-threonine in high levels and high yields even in the presence of high concentrations of glucose.

Abstract: The present invention relates to an L-threonine-producing chromosomal fadR gene knock-out microorganism. The present invention further relates to a method for producing L-threonine using a fadR knock-out microorganism. Mutated microorganisms of the present invention are capable of increased L-threonine production.