Abstract: A food freshness maintenance system is proposed. The system may include a chamber configured to accommodate food and a freshness maintenance device installed in the chamber. The freshness maintenance device may include a main body including an inlet through which air flows in and an outlet through which the air is discharged. The freshness maintenance device may also include an electromagnetic wave module, installed at the inlet of the main body, for ionizing food freshness reducing materials included in the air by emitting electromagnetic waves to the air. The device may further include a collection module, installed at the outlet of the main body, for collecting the ionized food freshness reducing materials from the air.

Abstract: This application relates to a modular electrostatic precipitator. In one aspect, the modular electrostatic precipitator includes a housing providing a flow path through which air is moved and a charging module configured to emit electromagnetic waves to the air. The precipitator may also include a first attaching/detaching unit configured to attach and detach the charging module to and from the housing and a particle collecting module configured to collect particles in the air by applying an electrostatic force to the air. The precipitator may further include a second attaching and detaching unit configured to attach and detach the particle collecting module to and from the housing.

Abstract: This application relates to a modular electrostatic precipitator. In one aspect, the modular electrostatic precipitator includes a housing providing a flow path through which air is moved and a charging module configured to emit electromagnetic waves to the air. The precipitator may also include a first attaching/detaching unit configured to attach and detach the charging module to and from the housing and a particle collecting module configured to collect particles in the air by applying an electrostatic force to the air. The precipitator may further include a second attaching and detaching unit configured to attach and detach the particle collecting module to and from the housing.

Abstract: This application relates to an air sterilizer and an air sterilization method using same. In one aspect, the air sterilizer includes a housing including a flow path through which air moves. The air sterilizer may also include a first sterilization module configured to emit an electromagnetic wave to the air to sterilize the air, and a second sterilization module configured to remove a microorganism in the air using an electrostatic force. The first sterilization module may adjust a wavelength of the electromagnetic wave so that an intensity of the electromagnetic wave is determined based on a type of the microorganism, by controlling a tube voltage of the electromagnetic wave.

Abstract: The present invention provides a method of producing polypeptide utilizing a fusion protein of A-B type in the following formula (I), by culturing transformed microorganism comprising DNA sequence encoding the desirable polypeptide; A-B (I). In the above formula (I), A is a fusion partner of 25 or more amino acid residues where aspartic and glutamic acid residues are incorporated to have a net negative charge of 30% or more, and B is the target protein to be produced. The target protein can be isolated from the fusion protein by employing enzymatic cleavage site etc. at the carboxyl-terminus of the fusion partner.