A new method from the Technical University of Denmark makes it possible to identify suitable fermentation bacteria within hours – including a strain that increases vitamin B2 levels in soy drinks.
Researchers at the Technical University of Denmark have developed a method that could significantly speed up the identification of bacteria for fermentation. In a new study, the researchers identified a lactic acid bacterium from bumblebees that can both acidify soy drinks and increase their vitamin B2 content.
The method enables the screening of millions of bacteria within a few hours by encapsulating them individually in microscopic droplets. According to the researchers, this could substantially reduce the development time for new starter cultures.
“Our research shows that it is possible to directly screen entire microbial communities quickly, and that promising bacteria can be identified from environmental samples without prior isolation and analysis of individual strains. This could make the development of new starter cultures faster and more targeted,” says Associate Professor Claus Heiner Bang-Berthelsen from the DTU National Food Institute in an article on www.food.dtu.dk.
Identified in wild bumblebees
The study addresses a well-known challenge in plant-based dairy alternatives: lower levels of certain vitamins and minerals compared with cow’s milk – including vitamin B2 (riboflavin).
The researchers therefore screened bacteria from the guts of wild bumblebees for their ability to both thrive in soy drinks and produce vitamin B2.
“Bumblebees live in close contact with plants, and their guts contain many microorganisms already adapted to plant-based environments. This made it relevant for us to investigate whether we could find bacteria in bumblebees capable of producing vitamin B2 in soy drinks,” says postdoc Hang Xiao from the DTU National Food Institute in the article.
Works in food – not only in the laboratory
One of the identified bacteria – Lactococcus lactis – proved particularly promising. In trials with actual food systems, it performed best in soy drinks, where it was able to grow and produce vitamin B2. Its performance was weaker in rice, oat and some almond drinks, which the researchers link to lower protein content in these products.
“The results suggest that the bacterium not only functions under laboratory conditions, but also in real food systems that contain a relatively high level of protein,” says Hang Xiao.
The bacterium produced up to 1.23 mg/L of riboflavin and also demonstrated the ability to utilise different sugars, making it relevant as a potential starter culture in plant-based fermentations.
Perspectives for fermentation
According to the researchers, the method could be applied more broadly than in this study – for example, to identify bacteria that produce other desirable compounds, provided these can be traced via fluorescence. However, the method requires a transparent medium and that the fluorescence is not harmful to the bacteria.
The work thus points to new opportunities for more targeted development of starter cultures – both for plant-based products and other fermented foods.
The study has been published in the scientific journal LWT – Food Science and Technology.
By Maja Løvstrup
Photo: Louis Reed, Unsplash
