Chen Zhang1,2, Feipeng Zhang1,2, Yang Wang1,2, Xiangzhu Shi3, Rong Fan4, Li Ni1,2. 1. Institute of Food Science and Technology, College of Biological Science and Engineering, Fuzhou University, Fuzhou, China. 2. Fujian Center of Excellence for Food Biotechnology, Fuzhou University, Fuzhou, China. 3. R & D Department, Fujian Xinminke Biotechnology Development Company, Fuzhou, China. 4. Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany.
Abstract
BACKGROUND: Monascus fermentation byproduct (MFB) is a biowaste generated after food colorants are extracted. Using MFB to produce probiotics (Bacillus subtilis) is a sustainable way for the entire production to be used as food or animal feed additives. However, due to the rigidity of the Monascus mycelium cell wall, B. subtilis cannot sufficiently utilize the nutrients in MFB, leading to low biomass production efficiency. We studied the effects of ultrasonic treatment, papain, β-glucanase, and chitosanase, and their combinations on improving the levels of soluble components from MFB. The effects of these treatments on mycelium cell walls were visualized using scanning electron microscopy, and their influence on B. subtilis production was analyzed. RESULTS: Ultrasonic treatment increased the soluble components by 210 g kg-1 , including 50 g kg-1 protein and 120 g kg-1 carbohydrates. An enzyme mixture increased the soluble components by 160 g kg-1 , including 30 g kg-1 protein and 90 g kg-1 carbohydrates. The combination of the two methods achieved the highest increase of soluble components (up to 400 g kg-1 ) leading to a maximum B. subtilis production of 1 × 1011 colony-forming unit mL-1 . This yield was about 20 times greater than that using untreated MFB and about eight times greater than treatments using only ultrasonic or enzymatic methods. CONCLUSION: The productivity of B. subtilis production using MFB as the sole medium can be greatly improved by ultrasound or enzymes, which cause the release of intercellular components or cell wall components.
BACKGROUND: Monascus fermentation byproduct (MFB) is a biowaste generated after food colorants are extracted. Using MFB to produce probiotics (Bacillus subtilis) is a sustainable way for the entire production to be used as food or animal feed additives. However, due to the rigidity of the Monascus mycelium cell wall, B. subtilis cannot sufficiently utilize the nutrients in MFB, leading to low biomass production efficiency. We studied the effects of ultrasonic treatment, papain, β-glucanase, and chitosanase, and their combinations on improving the levels of soluble components from MFB. The effects of these treatments on mycelium cell walls were visualized using scanning electron microscopy, and their influence on B. subtilis production was analyzed. RESULTS: Ultrasonic treatment increased the soluble components by 210 g kg-1 , including 50 g kg-1 protein and 120 g kg-1 carbohydrates. An enzyme mixture increased the soluble components by 160 g kg-1 , including 30 g kg-1 protein and 90 g kg-1 carbohydrates. The combination of the two methods achieved the highest increase of soluble components (up to 400 g kg-1 ) leading to a maximum B. subtilis production of 1 × 1011 colony-forming unit mL-1 . This yield was about 20 times greater than that using untreated MFB and about eight times greater than treatments using only ultrasonic or enzymatic methods. CONCLUSION: The productivity of B. subtilis production using MFB as the sole medium can be greatly improved by ultrasound or enzymes, which cause the release of intercellular components or cell wall components.