BACKGROUND: Moringa leaf is licensed as a new food ingredient and is rich in nutrients. However, owing to its high cellulose content, the nutrients are difficult to digest and absorb, which limits the product development and application of Moringa leaf. RESULTS: Four bacterial strains -Trichoderma reesei CICC 2626, Bacillus pumilus CICC 10440, Bacillus subtilis subsp. CICC 21934, and Bacillus sp. CICC 21942 -were chosen to ferment with Moringa leaf powder. The results of solid fermentation and liquid fermentation show that solid-state fermentation using Bacillus pumilus CICC 10440 in a 1: 60 ratio with Moringa leaf powder produced the greatest amount of soluble protein (285mg g(-1), 2.42 times higher than the control) in 24 h. Using a cellulase activity assay and western blotting, it was found that Bacillus pumilus CICC 10440 uses endoglucanase to dissolve the cellulose to release nutrients from the Moringa oleifera leaf. We expanded the fermentation scale of the Moringa oleifera leaf in a 200 L fermenter and produced a 50 kg batch of Moringa oleifera product. CONCLUSION: The results showing improvement in the nutrient release of Moringa leaf via microbial fermentation are a promising start and provide a basis for further product development of Moringa leaf. (C) 2017 Society of Chemical Industry