Acta Scientiarum Polonorum Technologia Alimentaria

Background. Whole-grain cereals are a vital source of nutrients. However, their bioavailability is often re­duced by anti-nutritional factors such as phytic acid and by the limited digestibility of cereal proteins. Sour­dough fermentation is a well-established biotechnological approach to mitigate these issues; however, the enzymatic traits required for this process are highly strain-specific and often uncorrelated among individual lactic acid bacteria (LAB) isolates. This study aimed to isolate and characterize LAB from rye sourdough to identify strains with strong phytase and proteolytic capacities.
Material and methods. A total of 12 LAB isolates were recovered from laboratory-prepared rye sourdough and screened for extracellular phytase and proteolytic activities. The top-performing isolates were subse­quently identified via 16S rRNA gene sequencing.
Results. Distinct functional specialization was observed among the isolates. Isolate PP-01 (Pediococcus pentosaceus) exhibited exceptionally high phytase activity (184.6 U/mg), whereas the strongest proteolytic activities were recorded for isolates LB-01 (Levilactobacillus brevis) and LP-03 (Lactiplantibacillus planta­rum), with specific activities of 51.93 U/mg and 42.97 U/mg, respectively.
Conclusion. The lack of association between phytase and proteolytic activities highlights the value of a mul­ti-strain starter culture for achieving comprehensive nutritional enhancement in rye-based products. Future work should evaluate the performance of these specialized strains under real-world bread-making conditions and investigate the genetic basis of their elevated enzymatic efficiency.