Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Shivani_Badiger_Thesis.pdf (2.08 MB)

ETD Abstract Container

Abstract Header

Investigation of interactions between Lactic Acid Bacteria in Consortia, and their impact on Enzymatic and Antimicrobial activities.

Badiger, Shivani S
http://orcid.org/0000-0001-8122-699X
http://rave.ohiolink.edu/etdc/view?acc_num=osu1626435463545301

Abstract Details

2021, Master of Science, Ohio State University, Food Science and Technology.
Lactic acid bacteria (LAB) are rarely found in single species in naturally occurring food fermentations such as yoghurt, kefir wine, etc. This is because synergistic microbial communities promote positive interactions between species thus promoting better growth, metabolite regulation, and antimicrobials production. These positive interactions can be facilitated by nutrient and metabolite exchange, changes in the extracellular environment (pH, ionic strength), quorum sensing, or the exchange of enzymes. In general, properties of LAB in monocultures have been extensively studied in different growth media, however, synthetic co-cultures are less explored and are gaining increasing research attention. Enzymatic activities such as proteolytic, lipolytic, and β-galactosidase can be correlated to nutrient exchange between LAB, flavor, and texture in food fermentations. Changes in these enzymatic and antimicrobial activities in co-cultures, and their impact on the growth of individual species remain unexplored. Here in this study, we present a comparison of growth of LAB in multiple co-cultures (consortia) over 20 h of growth, while also tracking the enzymatic and antimicrobial activities (bioactivities) of the co-cultures over time. Lactobacillus plantarum OSU-PECh-BB (Lp), Lactobacillus reuteri OSU-PECh-48 (Lr), and Pediococcus acidilactici OSU-PECh-3A (Pa) were chosen for this study and seven combinations were made from them (Lr, Lp, Pa, Lr-Lp, Lp-Pa, Lr-Pa, Lr-Lp-Pa). The growth of individual species was tracked in every combination using iv Real Time-qPCR and was compared across the combinations. Case of commensalism was observed between Lr and Lp, where Lp grew in higher counts with no impact on Lr. This result was attributed to the high proteolytic activity of Lr during the initial stages of growth. On the other hand, amensalism was observed between Lp and Pa, where Lp grew in significantly lower counts as compared to its monoculture with no impact on the growth of Pa (α=0.05). While the lipolytic activity in the extracellular fractions varied across co-cultures over time, there was no correlation found between growth and lipolytic activity. β-galactosidase activity in combinations containing Lr was strikingly higher than the other combinations. Thus, Lr can potentially be used in co-cultures to support the growth of other species in lactose-containing environments. Finally, the antibacterial activity of co-cultures measured using neutralized cell free supernatants (CFS) revealed that the growth rate of Escherichia coli in presence of Lr-CFS (0.193±0.003 h-1) was almost 8 times lower than E. coli grown alone (1.620±0.068 h-1). This was the case for all combinations containing Lr, while Lp and Pa showed the ability to lower the stationary phase of the pathogen. On the other hand, few combinations containing Pa significantly reduced the growth rate of Listeria innocua. Protein identification (LC-MS/MS) of CFS revealed the presence of additional antimicrobials in co-cultures that were not present in a monoculture. Detected antimicrobials included multiple peptidoglycan hydrolases, an endopeptidase, and proteins related to pediocin. This study thus highlights the impact of LAB co-cultures on bioactivities and antimicrobial activity.
Rafael Jiménez-Flores (Advisor)
Matthias Klein (Committee Member)
Osvaldo Campanella (Committee Member)
119 p.
Food Science; Microbiology; Molecular Biology
Lactic acid bacteria; co-cultures; enzymatic; antimicrobial activity

Recommended Citations

Citations

  • Badiger, S. S. (2021). Investigation of interactions between Lactic Acid Bacteria in Consortia, and their impact on Enzymatic and Antimicrobial activities. [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1626435463545301

    APA Style (7th edition)

  • Badiger, Shivani. Investigation of interactions between Lactic Acid Bacteria in Consortia, and their impact on Enzymatic and Antimicrobial activities. 2021. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1626435463545301.

    MLA Style (8th edition)

  • Badiger, Shivani. "Investigation of interactions between Lactic Acid Bacteria in Consortia, and their impact on Enzymatic and Antimicrobial activities." Master's thesis, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1626435463545301

    Chicago Manual of Style (17th edition)

osu1626435463545301
154
© 2021, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.