Isolation and Selection of Wild Bacillus Strains from Camelina sativa for Fermentation of the Camelina Oilseed Cake

This study demonstrated the potential of wild Bacillus strains isolated from Camelina sativa plants and rhizospheric soil for the bioconversion of camelina oilseed cake. Five selected strains (Z1, Z9, Z22, Z23, and Z26) exhibited promising enzymatic potential and the potential to improve the nutritional and functional properties of camelina cake. Both solid-state fermentation (SSF) and submerged fermentation (SF) increased the crude protein content and reduced the glucosinolate levels in ‘NS Slatka’ and ‘NS Zlatka’ camelina cake varieties, with the extent of these changes influenced by the bacterial strain, camelina variety, and fermentation mode. SSF generally showed a greater potential for improving the nutritional characteristics of the substrate, while fermentation also enhanced its antioxidant potential. Several wild isolates performed comparably to or better than the reference strain Bacillus subtilis ATCC 6051. Among the tested isolates, Z26 showed the most consistent overall performance, combining a broad enzymatic profile with favourable effects on the nutritional and functional properties of the fermented camelina cake under the investigated experimental conditions. MLSA (multilocus sequence analysis) putatively assigned Z26 to the B. amyloliquefaciens operational group, indicating a close relationship with B. amyloliquefaciens and B. velezensis. These findings highlight the potential of indigenous Bacillus strains as promising biocatalysts for the valorization of cold-pressed camelina oilseed cake and its conversion into a nutritionally improved feed ingredient.