optimum pH for YD5 & KH4 strains were 6.5 and 7 and the optimum temperature
was 30
C. The best medium for YD5 strain contained 3% hydrolyzed starch, 3%
corn steep liquor and sea minerals. The best medium for strain KH4 contained 2%
molasses, 3% corn steep liquor and sea minerals (Salehi Jouzani et al. 2011). Later
on, the mass production of strains YD5 and KH4 was optimized under batch
fermenter conditions. The previous optimized economic media were used under
fermenter conditions, and the effects of different factors, including quantity of
primary inoculation, aeration and pH were evaluated on the growth rate, and spore
and crystal production. The pre-culture concentration of 2% and the oxygen rate
ranging from 50 to 90%, were found to be optimal. Moreover, aeration during the
growth and spore-crystal production was necessary. Finally, following the optimized
growth condition, the maximum growth and the highest yield of spores and crystals
were achieved for KH4 (6.2 Â 10
9 CFU/ml) and YD5 (5.5 Â 10
9 CFU/ml) isolates
(Salehi Jouzani et al. 2011).
The success of a commercial bio-insecticide effectively depends on the optimization of the fermentation process (Fig. 10.5). Therefore, several studies have
focused to improve the production of Bt based insecticides. The nutritional parameters, nitrogen carbon and mineral sources of Bt strain H14 medium have been
modified to study their effects on Bt growth phase, sporulation and germination
(Sarrafzadeh 2012). The effect of different nutritional components such as glucose,
glycerol, sodium acetate, corn steep liquor, yeast extract, hydrolyzed casein,
(NH 4 ) 2 SO 4 , Ca
2+ , Mg
2+ and Mn
2+ were assessed. The effect of corn steep liquor
on bacterial growth, spore production and spore germination were more important
than other elements (Sarrafzadeh 2012). Marzban (2012b) optimized the solid
fermentation of three local Iranian Bt strains, KON3, KN3, KD2 using four solid
culture media: rice bran, wheat bran, rice flour and barley supplemented with mineral
salts, MnSO 4 , MgSO 4 , ZnSO 4 and FeSO 4 . The number of Bt spores and the
insecticidal activity of produced bacteria against H. armigera were investigated
and compared with that of HD-1 as a reference. Wheat bran was the best media
for Bt production (Marzban 2012b).
The cost of raw materials used in the mass production of a bio-insecticide is one
of the main expenditures in the production process. Therefore, there is a growing
Fig. 10.5 The fermenters of the Nature Biotechnology Company, Biorun, for microbial control
agents’ production
418
A. Khorramnejad et al.
was 30
C. The best medium for YD5 strain contained 3% hydrolyzed starch, 3%
corn steep liquor and sea minerals. The best medium for strain KH4 contained 2%
molasses, 3% corn steep liquor and sea minerals (Salehi Jouzani et al. 2011). Later
on, the mass production of strains YD5 and KH4 was optimized under batch
fermenter conditions. The previous optimized economic media were used under
fermenter conditions, and the effects of different factors, including quantity of
primary inoculation, aeration and pH were evaluated on the growth rate, and spore
and crystal production. The pre-culture concentration of 2% and the oxygen rate
ranging from 50 to 90%, were found to be optimal. Moreover, aeration during the
growth and spore-crystal production was necessary. Finally, following the optimized
growth condition, the maximum growth and the highest yield of spores and crystals
were achieved for KH4 (6.2 Â 10
9 CFU/ml) and YD5 (5.5 Â 10
9 CFU/ml) isolates
(Salehi Jouzani et al. 2011).
The success of a commercial bio-insecticide effectively depends on the optimization of the fermentation process (Fig. 10.5). Therefore, several studies have
focused to improve the production of Bt based insecticides. The nutritional parameters, nitrogen carbon and mineral sources of Bt strain H14 medium have been
modified to study their effects on Bt growth phase, sporulation and germination
(Sarrafzadeh 2012). The effect of different nutritional components such as glucose,
glycerol, sodium acetate, corn steep liquor, yeast extract, hydrolyzed casein,
(NH 4 ) 2 SO 4 , Ca
2+ , Mg
2+ and Mn
2+ were assessed. The effect of corn steep liquor
on bacterial growth, spore production and spore germination were more important
than other elements (Sarrafzadeh 2012). Marzban (2012b) optimized the solid
fermentation of three local Iranian Bt strains, KON3, KN3, KD2 using four solid
culture media: rice bran, wheat bran, rice flour and barley supplemented with mineral
salts, MnSO 4 , MgSO 4 , ZnSO 4 and FeSO 4 . The number of Bt spores and the
insecticidal activity of produced bacteria against H. armigera were investigated
and compared with that of HD-1 as a reference. Wheat bran was the best media
for Bt production (Marzban 2012b).
The cost of raw materials used in the mass production of a bio-insecticide is one
of the main expenditures in the production process. Therefore, there is a growing
Fig. 10.5 The fermenters of the Nature Biotechnology Company, Biorun, for microbial control
agents’ production
418
A. Khorramnejad et al.