Process development of cell and endotoxin

1
Process development of cell and endotoxin
production of Bacillus thuringiensis var kurstaki
SOMCHAI CHAUVATCHARIN, KHATTIYA
SONSANAM AND AMARET BHUMIRATANA
Faculty of Science, Mahidol University
2

• Bacillus thuringiensis (Bt)
• gram-positive bacteria
• e.g. btk, bta and bti
• produced different kinds of crystalline
  inclusion
• during the sporulation process
• wildly use as a biopesticides
• high specific, no effect on human and
• animals

3
Fish soluble as alternative protein source for
Btk cultivation
4
Table. Growth and spore formation of cell Btk.
using yeast extract (YE) and fish soluble (FS)
as nitrogen sources.  
5
The effect of nutrient concentrations on growth
and sporulation of Btk
6
Table. Comparison of cell growth, productivity
and spore formation of Btk cultured in media
containing different carbon and nitrogen
ratios.  
7
Process Development in Biorector Cultivation
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
BIOASSAYS OF PRODUCTS FROM Btk CULTIVATION
13
Table Comparison of insecticidal activity of
products from batch, fed-batch and commercial btk
products
Note Medium of batch and fed-batch experiment
was prepared acoording to equivalent of glucose
and FS concentration.
14
CONCLUSIONS
1.FS can replace YE as a potential nitrogen
source 2.Btk was shown as good protease producer
and susceptible with large protein
substrate. 3.Growth of Btk was promoted when
concentrations of glucose and FS were highly
supplied. However spore formations is delayed
when concentration of either glucose and FS were
increased.
15
4. Fed-batch cultivation is the suitable
technique for high cell density and early spore
formation at high productivity. 5. In fed-batch
cultivation feeding medium should contained both
of glucose and FS solution to promote cell growth
and sporulation. 6. The optimal ratio of
glucose and FS feeding medium using
for exponential fed-batch cultivation is at
11.24 (w/w). 7. Sufficient aeration is required
for growth as well as sporulation process.
16
8. Exponential feeding strategy is the suitable
strategy for high cell density and spore
formation with high insecticidal activity. 9.
Fed-batch cultivation provided higher
insecticidal activity than that of batch
cultivation, while spore formation could not be
good indicator for determining toxicity of Btk
products (data not shown).
17
Optimal strategy to obtain high cell density
with potent insecticidal activity should be -
cultivation in sufficient oxygen supplied
condition (bioreactor). - optimal
carbonnitrogen ratio in fed-batch cultivation
- exponential fed-batch cultivation (stop the
feeding soon after oxygen limited).
18
This research was supported by a grant from
Thailand Research Fund (TRF) senior research
scholarship NO. RTA/05/2540