Papers by Keyword: Solid-State Fermentation (SSF)

Abstract: In this paper, the optimum media supplemented to the basic substrate wheat bran (WB) for getting maximum soluble dietary fiber (SDF) production under solid state fermentation (SSF) by Hericium erinaceus was investigated. Soybean meal was suitable for mycelial growth as nitrogen source, four inorganic salts (KH2PO4、ZnSO4、FeSO4 and MgCl2) could increase SDF production significantly. Artificial neural networks (ANNs) and genetic algorithms (GA) formalisms were used for modeling the non-linear relationship between the fermentation media and SDF production and optimizing the model, respectively. After optimization, parameters of the five media supplemented to WB were (mg g-1 WB): soybean meal 124.3, KH2PO4 0.18, ZnSO4 0.6, FeSO4 0.2, MgCl2, 1.2. The SDF production increased to 13.06±0.51 g 100g-1 in the validation experiment, which was 4.68 fold as compared with control.

Abstract: Time courses of biomass, glucose and xanthan during solid state fermentation with various initial glucose concentrations were determined and analysed with a metabolic flux method. The use of 80 g L-1 instead of 40 and 20 g L-1 glucose led to higher xanthan production. In the stationary phase of cells, the velocities (ν) of all metabolic pathways are increased with increasing glucose concentration, while the highest specific rates (γ) of glucose consumption and xanthan generation was obtained when the initial glucose concentration was 40 g L-1. Hence, under solid-state fermentation, an abundant initial carbon source is advantageous in improving the velocity of xanthan production, while moderately abundant carbon sources promote the conversion of carbon to xanthan.

Abstract: The production of xylanase (TrxA) by Trichoderma reesei JL-1 in solid-state fermentation (SSF) was optimized by response surface methodology (RSM). Results revealed that factors of concentration of added ammonium sulfate, and moisture content had significant effect on the TrxA production (P<0.05). The maximum xylanase activity (485.0 U/g U/g dry fermentation product) was obtained at 2.9% the ammonium sulfate by employing wheat bran as the solid substrate, 61.6% moisture content and 59.5-h fermentation, which was close to the predicted one, and was 1.8 times as high as that of the basic medium. The optimum temperature and pH for TrXA activity were 45°C and pH 5.0, respectively. Over 90% of xylanase activity was retained after treatment of the enzyme by preincubation over a pH range of 3.0-5.0 for 1 h at 25°C. TrxA exhibited K_m and V_max values of 1.458mg/mL and 25.316 μmol/min/ml, respectively. In the presences of metal ions such as Mn²⁺the activity of the enzyme increased. Whereas strong inhibition of the enzyme activity was observed in the presences of Fe³⁺ and Ca²⁺.

Abstract: Air pressure amplitude serves as a critical control parameter in periodic pressure solid state fermentation process. Effects of air pressure amplitudes on thermostable xylanase production by Thermomyces lanuginosus SD-21 were investigated. Under the optimum periodic pressure amplitude, namely: at lower limit of 0.05 MPa and upper limit of 1.5 MPa. Among the lignocellulosic substrates tested, corn cob and wheat bran supported a high xylanase (EC 3.2.1.8) secretion by Humicola lanuginosa in solid-state fermentation (SSF). Enzyme production reached a peak in 96 h followed by a decline thereafter. Enzyme production was very high, xylanase activity 8237 IU /g of dry moldy bran can be obtained in the system compared with 4520 IU/g in conventional tray fermenter, cultivation of the mold in large enamel trays yielded a xylanase titer comparable with that in flasks. Parametric optimization resulted in a 45.13% increase in enzyme production in PPSSF.