Isolation, Screening, Identification of Cellulolytic Bacteria and Optimization of Factors Affecting FPUase Synthesis...

The screening of FPUase-synthesizing bacteria and optimization of hydrolysis conditions for alkaline pre-treated bagasse are key focuses of current research. This study systematically screened cellulose‑degrading bacteria from soil, mud, and cow liver samples, identifying HL04 as a robust FPUase‑producing strain. Based on 16S rRNA ribosome sequence, HL04 was identified as Bacillus safensis, a newly discovered microorganism capable of synthesizing FPUase. FPUase production conditions were optimized through single‑factor experiments analyzing fermentation time, substrate concentration, pH, and temperature. Using the Box-Behnken Design (BBD) under the response surface methodology (RSM), the study refined these factors to enhance FPUase production. The resulting second-degree polynomial model demonstrated high validity (R² = 0.9913), and statistically significant interactions (P < 0.05). Optimal conditions-12 g/L of substrate concentration, pH 7, and a fermentation temperature of 40 °C-yielded the highest FPUase activity of 61.5 U/L.