Impact of single and two-phase dissolved oxygen tension control on Bacillus thuringiensis cultivation and delta-endotoxin production

  • MOHAMED MAZMIRA MOHD MASRI 1Entomology and Integrated Pest Management Unit, Biology and Sustainability Research Division, Malaysian Palm Oil Board, 43000 Kajang, Selangor, Malaysia.
  • MOHD SHAWAL THAQIB MAIDIN
  • ARBAKARIYA BIN ARIFF

Abstract

Constant delta-endotoxin production is crucial in Bacillus thuringiensis (Bt) cultivation with aeration strategy plays a significant role in the process. In this study, the impact of two-phase dissolved oxygen tension (DOT) control strategies on the cultivation performance of Bacillus thuringiensis (Bt) was investigated using 5 L stirred tank bioreactor. Single-phase DOT control recorded low spore count (<5.0 x 1011 spore/mL) and low percentage of sporulation (<45%). Sporulation percentage was greatly reduced when the DOT was controlled at 80% throughout the cultivation. Unlike the two-phase DOT control, DOT set-up from high (80% saturation) to low (60% or 40% saturation) during the exponential growth phase promotes higher sporulation and stimulate delta-endotoxin synthesis. Cultivation with controlled DOT at 80% saturation during the active growth phase and then switched to 60% or 40% saturation at mid-exponential growth phase (after 6 h of cultivation) contributes to enhanced sporulation (˃ 60%), high maximum cell count (1.5 cfu/ml) with delta-endotoxin formed as early as 8 h of cultivation.  A high maximum specific growth rate, umax (˃ 0.1 h-1) is also essential in ensuring constant delta-endotoxin production. The two-phase DOT control strategy is an effective approach that contribute to constant production of delta-endotoxin and high-quality Bt production.

Published
2021-03-29
How to Cite
MOHD MASRI, MOHAMED MAZMIRA; MAIDIN, MOHD SHAWAL THAQIB; ARIFF, ARBAKARIYA BIN. Impact of single and two-phase dissolved oxygen tension control on Bacillus thuringiensis cultivation and delta-endotoxin production. Malaysian Applied Biology Journal, [S.l.], v. 50, n. 1, mar. 2021. ISSN 2462-151X. Available at: <http://myjms.mohe.gov.my/index.php/mabjournal/article/view/11262>. Date accessed: 21 apr. 2021.