Screening of metabolite regulating lactic acid production of exiguobacterium aurantiacum ATCC49676 by metabolic fingerprint analysis

Abstract

A strain of Exiguobacterium aurantiacum ATCC49676 was found to be of great potential to produce lactic acid (LA). In order to screen the metabolites that might regulate or affect the acid yield, a relative higher LA production condition was defined through full factorial experiment design. Fresh cultures harvested from the basic and the higher LA production conditions were subjected to metabolic fingerprint analysis by gas chromatography-mass spectrometry. Significance analysis indicated a distinct change of an intercellular metabolite-L-glutamic acid (Glu). When ATCC49676 was treated by Glu, LA yield declined with the increasing added Glu concentrations. Relative enzyme quantification confirmed that Glu decreased the intracellular lactate dehydrogenase content. This study proved the merit of metabolic fingerprint analysis in exploring the phenotype specific intracellular metabolite and its potential roles in improving industrial fermentation efficiencies. © 2012 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.