Isolation and characterization of lactic acid bacteria (LAB) from mussels (Perna indica) and determination of bacteriocin activity using the direct assay method

• Main Authors: Concepcion, Jake Randolph M., Cinco, Ryan D.
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Lactic acid bacteria; Mexilhao mussel > Microbiology; Bacteria; Bacteriology; Biology
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/5282
• Institution: De La Salle University

Lactic acid bacteria or LAB are microaerophilic, Gram-positive, catalase and oxidase negative rods and cocci. This study aimed to isolate lactic acid bacteria (LAB) from mussels (Perna indica). The interest of this study focused on mussels (Perna indica) because review of literature showed that this seafood has not been studied yet for the presence of lactic acid bacteria. It also aimed to characterize the putative LAB by preliminary cultural and phenotypic tests such as: colonial and microscopic morphology. Gram-positive, non-spore forming, catalase and oxidase negative, lactose fermenting, were classified as putative LAB. Biochemical assays were also performed to verify that what were isolated could be considered as putative LAB. These included reaction in TSI or triple sugar iron, urease test, lactose fermentation and citric acid utilization test. The bacterial isolates were also tested for their physiological characteristics which included growth in different temperatures, growth in different salt concentration and growth in different pH concentration. The presence of bacteriocin activity was determined using the direct assay method with the indicator strain, Listeria innocua. The results showed that the isolated LAB could inhibit this indicator strain by developing a zone of inhibition.