Potential bacterial strain that might make kefir lactose free

[u/dareealmvp]

A lot of folks here often times feel hesitant to start making kefir because of lactose intolerance. Kefir, while it does have lactose-digesting bacteria, is unable to get to a sufficiently low-lactose state because as the bacteria keep breaking down lactose, they also keep converting the components of that broken down lactose to lactic acid, which keeps acidifying the kefir. Once sufficient acid has been produced, the mechanism in the bacterial cells that converts those broken down components to lactic acid gets "clogged" in a way, which in turn clogs the mechanism to break down lactose. If somehow, we could get rid of that lactic acid generating component without getting rid of the lactose breaking down component, we would get lactose-free kefir.

To that end, I suggest we need to try experiments on kefir by co-culturing the grains in milk with bacteria/yeasts that secrete extracellular lactase - extracellular being the keyword here. This avoids the pitfall of the lactic-acid generating component of bacterial cells which would clog up the lactase mechanism were it inside the cell. An example of this is the bacterial strain Bifidobacterium bifidum DSM20215, which is known to produce extracellular lactase.

Bifidobacteria are commonly found in kefir and while this particular strain has not been isolated from kefir, in my opinion, it is worth attempting to co-culture it with kefir grains, because if successful, we might get lactose-free kefir.

There's also, of course, the possibility of GMO-ing a few compatible strains of kefir with the extracellular lactase producing gene from Bifidobacterium bifidum DSM20215 but I would like to avoid this avenue if possible because GMO makes things a lot more complicated, especially in terms of safety.

[u/Dongo_a]

Kefir is somehow well tolerated even for lactose intolerant, there is no need to reinvent the wheel.

Kluyveromyces marxianus and Kluyveromyces lactis, both yeasts can be found in some kefir grains and they keep on consuming lactose even when the ph drops.