Detection and Analysis of Bacillus subtilis Growth with Piezoelectric Quartz Crystal Impedance Based on Starch Hydrolysis
✍ Scribed by Yaohui Wu; Qingji Xie; Anhong Zhou; Youyu Zhang; Lihua Nie; Shouzhuo Yao; Xiangtao Mo
- Book ID
- 102563948
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 120 KB
- Volume
- 285
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
A piezoelectric quartz crystal (PQC) impedance method based on the ␣-amylase-catalyzed hydrolysis of starch present in a culture medium has been developed for in situ monitoring of the whole growth process of Bacillus subtilis and the variation in the activity of ␣-amylase during bacterial growth. An S-shaped response behavior was observed for ⌬f 0 , and simultaneously inverse S-shaped responses were found for ⌬R 1 and ⌬L 1 . The ratio of ⌬R 1 to ⌬f 0 or ⌬L 1 coincided well with that calculated from Martin's equations reflecting the solution density-viscosity effect, suggesting that the continuing change in liquid loading onto the PQC surface causes significant variation in ⌬f 0 , ⌬R 1 , and ⌬L 1 . Bacterial growth equations were derived from the kinetics of the enzyme-catalyzed hydrolysis of starch, which fit well with the experimental responses of ⌬f 0 , ⌬R 1 , and ⌬L 1 . Kinetic parameters of bacterial growth, including the asymptote (A), the maximum specific growth rate ( m ), and the lag time (), were obtained and were in good agreement with those obtained from the pour plate count method. The variation in the activity of ␣-amylase exhibited peaktype behavior with its maximum value at the later stage of the log phase. In addition, the influence of initial bacterial concentration was also investigated.