Fermented food products are trendy and carrying out fermentations at home is becoming increasingly popular. It’s fun, gives you an enormous richness in flavour and it is believed to be healthy by challenging your body with a large diversity of bacteria. A previous blog on fermentative product diversification on an industrial scale was written by my colleague Martijn Bekker. In this blog I would like to dive deeper to discuss bacteria with a proven or suggested health benefit.
Where Metchnikoff focused on one healthy bacterial species naturally present in Bulgarian yogurt, today’s research on potential beneficial organisms focuses on bacteria from relevant niches such as the human gut, oral cavity and skin. Genetically and physiologically these organisms are very diverse, resulting in demanding cultivations, downstream processing, but also complex consumption formats. These aspects are major challenges compared to existing products with healthy bacteria, mostly belonging to a fastidious growing group of lactic acid bacteria.
At Nizo, we are at the forefront of this field of research – from identifying potentially interesting microbes via bioinformatics to understanding their physiology to producing these organisms for human consumption. The human gut, for example, is a complex and strictly anaerobic eco-system low in readily available carbon sources, but high in fibres, organic acids and mucus-derived components.
Robotic screening facilities are available for designing and testing media to ensure proper growth of bacteria, selected from these niches. Subsequently selected strains were produced in the Nizo food-grade processing centre and are currently being tested in clinical trials. Part of the success in this field is based on the use of one closed and well de-aerated system, including sterilisation and de-aeration of complex media in UHT systems. Using UHT is one of the available options that enables us to maintain maximal nutritional value and minimise Maillard reactions. This strictly anaerobic setup enabled us to cultivate strict anaerobes to high cell densities on 40, 600 litre scale, and even 4,500 litre will be available in the near future. Although the used media were food grade, removal of medium components from the final application is – in most cases – crucial. For this, we used membrane filtration followed by diafiltration. Final cell concentrates were standardised and formulated by bulk freezing, freezing in portion packs for direct consumption (1-20ml) or pelletising as preparation for freeze drying.
Two variations on this process are worth mentioning. First, the possibility to concentrate the permeate by a set of membrane technologies. This way specific fractions can be concentrated, which can be interesting for various reasons. These concentrates might also be very suitable for formulation by, for example, spray drying. Secondly, in case cells where oxygen is stable, we successfully executed strategic research on spray drying these bacterial concentrates. This research did not only focus on the process of spray drying, but also influencing the stress response of the bacterial cells by modification of growth parameters, and also by strain optimisation by, for example, adaptive evolution. Based on that research, a new powdering approach was developed, enabling cost-effective formulation of heat-labile compounds in several dry formats such as a spray-dried powder. This can result in a powder with similar properties to a spray-dried power.
The combination of disciplines at Nizo allows for successful identification and production of potentially healthy bacteria. At the same time these specialised productions are very exciting, and a crucial element in current research towards a new generation of healthy microbes applied in food and pharma. I can only say, take part in it and enjoy the action!
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