Isolation and evaluation of lactic acid production by local isolated Lactic Acid Bacteria

Abstract

Lactic acid is an organic acid which has numerous applications in the food, pharmaceutical, cosmetics and chemical industries. New application such as biodegradable plastic made from poly (lactic) acid and its production is currently attracting a great deal of research and development.Lactic acid can be produced commercially by either chemical synthesis or fermentation, but in recent years fermentation process has become more industrially successful because of the increasing demand for naturally produced lactic acid.This study was embarked upon to obtain laboratory strains of lactic acid bacteria (LAB) from some local raw milk with potential for the production of lactic acid.Some samples of local raw cow milks collected from different regions of Iran were transferred to research lab under the aseptic conditions.Lactic acid bacteria were grown on specific culture media (M17, KA, MRS) and a total of 26 isolates were screened and evaluated about acidification on the basis of their milk pH lowering potentials. Finally, Enterococcus faecium subsp was determined as the best acidifier LAB. Rich biodiversity of natural environments can be considered as good sources of new LAB species or strains.