[Isolation and in vitro metabolic characterization of a lactate-utilizing bacterium from goat rumen].
OBJECTIVE
A lactate-utilizing, propionate-producing bacterium, strain L9, was isolated from rumen of goat fed with high concentrate by utilizing modified Hungate technique and anaerobic culture technique. The effect of the strain L9 culture on the rumen fermentation was further studied.


METHODS
According to the characteristics of morphology, physiology, biochemistry tests and sequence comparison of 16S rRNA gene, strain L9 was identified as selenomonas ruminantium. The influence of strain L9 culture on in vitro rumen fermentation was studied using mixed rumen micro-organisms of goats as inoculums.


RESULTS
The results of the metabolism experiment showed that it was capable of using lactate as the sole carbon source, and 90 mmol/L lactate in LH medium could be completely utilized after 24 h incubation. As compared with the control, strain L9 culture addition significantly increased the total volatile fatty acids (TVFA), the percentage of propionate and pH value, while reduced the ratio of acetate to propionate and lactate production (P < 0.05).


CONCLUSIONS
The results suggested that strain L9 can reduce lactic acid production and enhance the TVFA and propionate production in in vitro fermentation, and thus could be beneficial for the fermentation of rumen microorganisms.
Long
Liming
L
Laboratory of Gastrointestinal Microbiology, College ofAnimal science and Technology, Nanjing Agricultural University, Nanjing 210095, China. longlimingyouxiang@yahoo.com.cn
Mao
Shengyong
S
Su
Yong
Y
Zhu
Weiyun
W
D000821:Animal Feed; D000818:Animals; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005260:Female; D005285:Fermentation; D006041:Goats; D007773:Lactates / Q000378:metabolism*; D007774:Lactation; D011247:Pregnancy; D012417:Rumen / Q000382:microbiology*; D020357:Selenomonas / Q000302:isolation & purification* / Q000378:metabolism
D005232:Fatty Acids, Volatile; D007773:Lactates