title: The effect of gas double-dynamic on mass distribution in solid-state fermentation.
abstract: The mass distribution regularity in substrate of solid-state fermentation (SSF) has rarely been reported due to the heterogeneity of solid medium and the lack of suitable instrument and method, which limited the comprehensive analysis and enhancement of the SSF performance. In this work, the distributions of water, biomass, and fermentation product in different medium depths of SSF were determined using near-infrared spectroscopy (NIRS) and the developed models. Based on the mass distribution regularity, the effects of gas double-dynamic on heat transfer, microbial growth and metabolism, and product distribution gradient were systematically investigated. Results indicated that the maximum temperature of substrate and the maximum carbon dioxide evolution rate (CER) were 39.5°C and 2.48mg/(hg) under static aeration solid-state fermentation (SASSF) and 33.9°C and 5.38mg/(hg) under gas double-dynamic solid-state fermentation (GDSSF), respectively, with the environmental temperature for fermentation of 30±1°C. The fermentation production (cellulase activity) ratios of the upper, middle, and lower levels were 1:0.90:0.78 at seventh day under SASSF and 1:0.95:0.89 at fifth day under GDSSF. Therefore, combined with NIRS analysis, gas double-dynamic could effectively strengthen the solid-state fermentation performance due to the enhancement of heat transfer, the stimulation of microbial metabolism and the increase of the homogeneity of fermentation products.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: hzchen@home.ipe.ac.cn.
authors.forename: Hong-Zhang
authors.initials: HZ
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Hong-Qiang
authors.initials: HQ
authors.lastname: Li
mesh_terms: D000392:Air Movements; D018533:Biomass; D019149:Bioreactors; D002245:Carbon Dioxide / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism*; D004867:Equipment Design; D005285:Fermentation; D006358:Hot Temperature; D007218:Industrial Microbiology / Q000295:instrumentation / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D025282:Mycelium / Q000254:growth & development / Q000648:ultrastructure; D010940:Plant Proteins / Q000378:metabolism*; D018547:Plant Stems; D019265:Spectroscopy, Near-Infrared; D014242:Trichoderma / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure; D014908:Triticum; D014867:Water
chemical_list: D010940:Plant Proteins; D014867:Water; D002245:Carbon Dioxide; D002480:Cellulase
keywords: Cellulase; Enzyme production; Gas double-dynamic solid-state fermentation (GDSSF); Mass distribution gradient; Near-infrared spectroscopy (NIRS)