Liquid products vs powder products
We find on the market many products made from freeze-dried bacteria. It is true that this technique of dehydration increases the product shelf life but has however many disadvantages.
Indeed, this process involves changes of aggressively product temperature for the micro-organisms particularly during the freezing phase, which is not without consequences for the cells. The cell walls of gram-negative bacteria with peptidoglycan layer thinner than that of Gram-positive bacteria, are much more likely to break during the process of desiccation and rehydration (Pembrey et al., 1999).
Effect of storage time on the nitrogen removal activity of Nitrosomonas and Nitrobacter (Grunditz and Dalhammar, 2001).
Reactivation of gel immobilized nitrifiers after preservation by freezing, drying or freeze drying with different protectants added: initial activity and ratio of the original activity conserved, estimated from activity measurements during the first 2-14 h of regeneration in batch mode; time before the original activity was regenerated; maximum nitrite accumulation during regeneration relative to the ammonium removal rate (Vogelsang et al., 1999).
Another parameter that influences cell viability is the rate of rehydration. Mille et al. (2003). The best results were achieved by rehydrating the cells over 16 min with -0,136 MPa/s which enabled the survival of 36,4% of bacteria.
Liquid products that we offer only contains alive bacteria and ready to biodegrade. Their culture medium being depleted nutrients and oxygen-free, they find themselves in lag phase. They are immediately efficient as they are introduced into the medium to be treated. Pre activation can significantly increase their number and increase the effectiveness of treatment by providing bacteria the nutrients necessary for their development.