Impact of single and two-phase dissolved oxygen tension control on Bacillus thuringiensis cultivation and δ-endotoxin production
Constant δ-endotoxin production is crucial in Bacillus thuringiensis cultivation with aeration strategy playing a significant role in the process. In this study, the impact of DOT control strategies on the cultivation performance of B. thuringiensis was investigated using a 5-L stirred tank biorea...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Penerbit Universiti Kebangsaan Malaysia
2021
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| Online Access: | http://journalarticle.ukm.my/17894/ http://journalarticle.ukm.my/17894/1/73-84%2B%2B%2BMohamed%2BMazmira%2BMohd%2BMasri.pdf |
| Summary: | Constant δ-endotoxin production is crucial in Bacillus thuringiensis cultivation with aeration strategy playing a significant
role in the process. In this study, the impact of DOT control strategies on the cultivation performance of B. thuringiensis
was investigated using a 5-L stirred tank bioreactor. Single-phase DOT control recorded low spore count (<5.0 × 1011
spore/mL) and low percentage of sporulation (<45%). Two-stage DOT control cultivation with DOT at 80% during the
active growth phase, followed by a switch to 60% or 40% at mid-exponential growth phase contributed to enhanced
sporulation (>60%), high maximum cell count (1.5 cfu/mL) with δ-endotoxin formed as early as 8 hr of cultivation. A high
maximum specific growth rate, μmax (>0.1 h-1) was also essential in ensuring δ-endotoxin production. High cell count obtained
in cultivation with DOT level of 80% saturation during active growth was concurrent with high cell count, high μmax, fast
generation time, high OUR, high CER value, and high respiratory quotient (RQ) value. During the two-phase DOT control
cultivation, low RQ values were reported. The result showed that the exhaust gas data could be used to monitor B.
thuringiensis cultivation performance. |
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