Solid-state fermentation ofMoringa oleiferaleaf meal usingBacillus pumilusCICC 10440

BACKGROUND Moringa leaf is licensed as a new food ingredient and is rich in nutrients. However, due to its high cellulose content, the nutrients are difficult to digest and absorb, which limits the product development and application of Moringa leaf. RESULTS We chose four bacterial strains—Trichoderma reesei CICC 2626, Bacillus pumilus CICC 10440, Bacillus subtilis subsp. CICC 21934, and Bacillus sp. CICC 21942—to ferment with Moringa leaf powder. The results of solid fermentation and liquid fermentation show that the solid-state fermentation using Bacillus pumilus CICC 10440 in a 1:60 ratio with Moringa leaf powder produced the greatest amount of soluble protein (285 mg/g, 2.42 times higher than the control) in 24 h. Using a cellulase activity assay and western blotting, we 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 the further product development of Moringa leaf.