Biofouling of ultrafiltration membrane by dairy fluids: Characterization of pioneer colonizer bacteria using a DNA metabarcoding approach.

Biofouling of filtration membranes is a major quality and performance issue for the dairy industry. Because biofilms that survive cleaning cycles become resistant over time, prevention strategies limiting the adhesion of bacteria to membranes should be prioritized for sustainable control of biofouling. However, this cannot be achieved because the pioneer bacteria colonizing these membranes are still unknown. Consequently, the objective of this study was to characterize pioneer bacteria on the filtration membrane surface and to measure the effect of filtration operational parameters on their diversity. Thus, milk and cheese whey were filtered for 5 h in concentration mode at 10 and 40°C using a laboratory-scale crossflow filtration system equipped with flat-sheet ultrafiltration membranes. Pioneer colonizer bacteria found on membranes after a chlorinated alkaline cleaning cycle were identified using a metabarcoding approach targeting the 16S ribosomal RNA genes. Our results suggested that prevention strategies targeting biofouling should consider the nature of the filtered fluid and the feed temperature (36.15 and 5.09% of the variances observed on membranes, respectively), as well as the microbial environment of the dairy processing plant. In the future, it is hypothesized that cleaning prevention strategies will be specific to each dairy processor and their operational parameters.