A β-mannanase-producing lactic acid bacteria (LAB) was identified as Weissella cibaria F1 according to physiological and biochemical properties, morphological observations, partial sequence of 16S rRNA gene and API 50 CHL test. In order to improve the yield of β-mannanase, the response surface methodology (RSM) was originally used to optimize the fermentation conditions. The optimization results showed that when the konjac powder, glucose, and initial pH were 9.46 g/L, 14.47 g/L and 5.67, respectively, the β-mannanase activity increased to 38.81 ± 0.33 U/mL, which was 1.33 times compared to initial yield (29.28 ± 0.26 U/mL). This result was also supported by larger clearance on the konjac powder-MRS agar plate through Congo Red dyeing. The W. cibaria F1 β-mannanase could improve the clarity of five fruits juice, i.e., apple, orange, peach, persimmon and blue honeysuckle. Among these, peach juice was the most obvious, clarity increasing by 12.8%. These results collectively indicated that W. cibaria F1 β-mannanase had an applicable potential in food-level fields.
Keywords: Weissella cibaria; juice clarification; optimization; response surface methodology; β-mannanase.