The current study aimed to determine fermentation quality, aerobic stability, and enzyme soluble organic matter (ELOS) of wheat straw silage by replacing homofermentative (HM) and homofermentative+heterofermentative (HM+HT) lactic acid bacteria (LAB) inoculants with kefir as silage additives. For this purpose, commercially available Biotal Plus II (HMLAB), Biotal Buchneri 500 (HM+HTLAB), and MYStarter KF (KF) were used as silage additives. Four kg of wheat straw, about 400 g/kg, and 6.0 log cfu of inoculants or kefir were used in each treatment group and replicate. Including the control group (CON), a total of 12 laboratory-type silos (3 replicates and 4 groups) were opened after 45 days. The dry matter (DM), crude ash (CA), acid detergent lignin (ADL), and water-soluble carbohydrate contents of silages were not affected by the addition of HMLAB, HM+HTLAB, and KF (P>0.05). The KF group had the lowest pH value (4.32), NH3-N content (71.97 g/kg TN), and higher lactic acid content (43.11 g/kg DM). The crude protein (CP) ratio was decreased in HMLAB (5.95%) and HM+HTLAB (5.63%) groups and increased in the KF group (4.54%, P