Yoghurt, kefir, kombucha, probiotics and our own healthy gut microbiomes share a bacteria in common – Lactic Acid Bacteria.

Lactic Acid Bacteria (LABs) are beneficial bacteria and one of the earliest colonisers of the infant gut. The name Lactic Acid Bacteria or LABs for short comes from fact that these bacteria produce lactic acid as the major metabolic end product of carbohydrate fermentation.

As a group, LABs encompass a wide range of bacterial species. Two common Lactic Acid Bacteria are Lactobacillus spp. and Enterococcus spp. These bacteria are key members of the human gut microbiome and also play an important role in food production. They are often one of the main players in commercially available probiotics.

Multifaceted and multifunctional microbes in our gut microbiome

Lactic Acid Bacteria are an integral part of a healthy gut microbiome.

Research has shown that the microbiome of our gut plays an important role in maintaining normal gut function as well as in our overall health and wellbeing. The cells which line our gastrointestinal tract work hand-in-hand with our resident microbiota to protect us from potentially harmful microbial invaders.

Lactic acid bacteria help keep us safe from potential infections. They have an arsenal of weapons to stop any potential disease-causing microbes from evading our gut! This includes the production of lactic acid, hydrogen peroxide, and small antimicrobial peptides with specific bacterial targets known as bacteriocins. The production of lactic acid as well as acetate by these bacteria helps to keep the pH of our guts acidic. The low pH helps to create and maintain a hostile and unwelcoming environment for any potential pathogens which could make us ill, and so give a protective effect.

We can encourage more Lactic Acid Bacteria to live in our gut microbiome through our diet. Research has shown that our healthy gut microbiomes benefit greatly from a diet rich in a wide variety of fruits and vegetables.

Lactic Acid Bacteria in the food industry

Along with their important role in our gut health, Lactic Acid Bacteria are also key to the food industry.

They’re often used as starter cultures for fermented dairy products. Cheeses, yoghurts, and fermented milk products such as the delicious and creamy kefir are all made with Lactic Acid Bacteria.

The bacteria can also be found in traditional fermented foods such as Korean Kimchi and the European Sauerkraut. Besides adding flavour, texture, and nutritional value to these foods, Lactic Acid Bacteria also help to preserve foods against spoilage. These bacteria can have antimicrobial activity against bacteria, yeast, and filamentous fungi that can make food go off. This allows Lactic Acid Bacteria to be used as bio-preservatives, extending the shelf life of our favourite cheeses!

Probiotic potential

Probiotics are foods or supplements which contain a mix of beneficial microorganisms that can help maintain or improve the healthy microbiome within our guts.

Lactobacilli are one of the main bacteria used in commercially available probiotics. As we learn more about the importance of having a healthy gut microbiome and its effects on our overall health, probiotics have been proposed as potential aids against a number of ailments including allergies such as atopic dermatitis, gut related illnesses such as ulcerative colitis and inflammatory bowel disease, and may even have benefits in the management of mental health conditions such as depression.

However, due to the complexity of the human gut microbiome its potential systemic involvement in disease development requires further research.

Lactic acid bacteria for shaping the human gut microbiome

Here at the Quadram Institute we are looking at the potential of using LABs such as Lactobacillus species for the modulation of the human gut microbiome. This would allow us to influence bacterial communities in dysbiosis, shaping it towards healthier outcomes. Dysbiosis is an imbalance or disruption to the bacterial population within the microbiome, this could be due to a loss in beneficial bacteria, the overpopulation of pathogenic bacteria, or a loss in bacterial diversity, all of which could have a negative impact upon our health.

My Lactic Acid Bacteria of interest is a producer of multiple bacteriocins with antimicrobial activity against a wide variety of bacteria. My research includes looking at antimicrobial activity as well as the genes which encode for these bacteriocins. I aim to understand how this particular Lactic Acid Bacteria and its bacteriocins can affect a gut microbiome using synthetic microbial communities along with an in vitro colon model.

The use of such bacteria as probiotics would potentially allow for the better long-term management of gut related disorders such as inflammatory bowel syndrome and ulcerative colitis. The antimicrobial properties of the Lactic Acid Bacteria could be used as a form of biocontrol against the pathogenic bacteria such as C. perfringens, either in place of or in conjunction with standard antibiotic treatments.

Lactic Acid Bacteria are full of fascinating biology and probiotic potential waiting to be explored here at the Quadram Institute.