Plant-based diets are gaining popularity due to perceived advantages in terms of health, ethics and environmental impact. Microbial fermentation of plant-based milk alternatives (PBMAs) has the potential to enhance their nutritional properties by increasing bioavailability of nutrients, antioxidant activity and release of polyphenols. Six PBMAs (almond, soy, oat, coconut, hazelnut and cashew) were fermented using Lactic Acid Bacteria (LAB), with five strains originating from plant sources and six from dairy sources. PBMAs were inoculated with each strain at 2%. Viable cell counts and pH analyses were conducted immediately after inoculation and again after 24hr of fermentation at 37 ºC, to determine if the LAB strains could proliferate in the PBMA matrix. The glycolytic and proteolytic activities present in PBMA fermentates were assessed against non-fermented negative controls. Ten of the eleven strains demonstrated a minimum of 1-log increase in each variety of PBMA after 24hrs of fermentation. Fermentates selected for screening in the micro-Matrix bioreactor platform (Applikon®), an ex-vivo model of the distal colon included strains from plant and dairy sources. Selected fermented PBMAs (1ml) and non-fermented controls were added of the micro-Matrix reactions every 24hrs for a total duration of 96hrs of fermentation at which time aliquots were collected for analysis. LAB fermentation data and gut microbiota modulation capacities of twenty fermentates will be presented.