ISOLATION AND IDENTIFICATION OF LACTIC ACID BACTERIA FROM DAIRY SLUDGE SAMPLE FOR FERMENTATION OF LACTIC ACID, WOLAITA SODO, SOUTHERN ETHIOPIA

KRISHNA MOORTHY SIVALINGAM¹*
¹Department of Biology, College of Natural and Computational Sciences, Wolaita Sodo University, Wolaita Sodo, Post Box No.: 138, Ethiopia
* Corresponding Author : skrish.microbiologist@gmail.com

Received : 03-02-2021     Accepted : 26-02-2021     Published : 28-02-2021
Volume : 13     Issue : 2       Pages : 1942 - 1948
Int J Microbiol Res 13.2 (2021):1942-1948

Keywords : Lactic acid bacteria, Lactobacillus, Lactococcus, Dairy sludge and Fermentation
Academic Editor : Dr Renu Agrawal, Dr Jai P. Rai, Rajpal Diwakar, Dr Vijaya Lakshmi V
Conflict of Interest : None declared
Acknowledgements/Funding : Authors are thankful to Department of Biology, College of Natural and Computational Sciences, Wolaita Sodo University, Wolaita Sodo, Post Box No.: 138, Ethiopia
Author Contribution : Sole author

The aim of this study was isolation and identification of lactic acid bacteria from dairy sludge samples collected from SNNPR Bureau of Livestock and fishery resources, Wolaita Sodo dairy cattle production center. For isolation, all the samples were serially diluted and inoculated to MRS agar using pour plate technique. Well-isolated 5 different colonies were picked from each plate and marked as LAB1, LAB2, LAB3, LAB4 and LAB5 (LAB – Lactic Acid Bacteria) for further experiments. All these five isolates were identified as Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus fermentum, Lactococcus lactis and Leuconostoc mesenteroides by using different morphological, physiological and biochemical tests. All the isolates were Gram-positive, rods or cocci shaped, catalase negative, non-motile, able to grow at low salt concentration and ferment carbohydrate. All the isolates were fallen to two genera as follows: LAB1, LAB2 and LAB3 belong to genus Lactobacillus and LAB4 and LAB5 belongs to genus Lactococcus. Fermentation study was performed in 250ml flasks containing 100ml of sterile cow milk with 1ml of overnight active LAB isolates. All the inoculated flasks were incubated under rotary shaker incubator at 130rpm for 24h to 72hrs. The highest amount of titrable acid (TA) was observed from isolate Lactococcus lactis (4.74±0.21%) followed by Lactobacillus fermentum (4.38±0.28%), Leuconostoc mesenteroides (4.2±0.15%) and Lactobacillus acidophilus (4.05±0.32%) at temperature 37ºC and 72hours of incubations whereas the lowest TA observed from isolate Lactobacillus brevis (3.75±0.17%). Therefore, the present study concludes that the lactic acid bacterial isolates such Lactobacillus acidophilus, Lactobacillus fermentum, Leuconostoc mesenteroides and Lactococcus lactis can be used as inoculum to produce lactic acid by fermentation