Method for preparing highly concentrated killed bacteria using membrane filter and killed bacteria prepared thereby

A method for preparing killed lactic acid bacteria using a bioreactor including a culture device and a membrane filter, the membrane filter including a first membrane filter and a second membrane filter and the bioreactor having a structure in which a fluid added to the culture device independently passes through the first membrane filter and the second membrane filter and then is delivered again to the culture device, the method comprising:

• adding a medium inoculated with live lactic acid bacteria into the culture device;
• culturing and concentrating the live lactic acid bacteria by allowing the medium inoculated with the live lactic acid bacteria to pass through the first membrane filter, comprising:
• reducing sizes of the live lactic acid bacteria by a shear force applied to the medium by the first membrane filter, and
• controlling the shear force by controlling a flow rate of the lactic acid bacteria medium passing through the first membrane filter;
• killing the cultured and concentrated live lactic acid bacteria to prepare killed lactic acid bacteria;
• concentrating the killed lactic acid bacteria by allowing the medium including the killed lactic acid bacteria to pass through the second membrane filter;
• and
• drying and pulverizing the concentrated killed lactic acid bacteria.