Stabilization and increased production of insecticidal crystal proteins of Bacillus thuringiensis subsp. galleriae in steady- and transient-state continuous cultures

Sachidanandham, Ramaiah; Jenny, K.; Fiechter, Armin; Jayaraman, Kunthala

doi:10.1007/s002530050881

Cited by 11 publications

(11 citation statements)

References 13 publications

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“…4C and D) and (ii) adaptive mutation (Cohan, 2004) or horizontal gene transfer (Alm et al, 1999;Baba et al, 2002;Beres et al, 2002) could be principle mechanisms for the evolution of B. mojavensis to be a dominant colonizer of the hyperosmotic desert soils (Bacon and Hinton, 2002;Roberts and Cohan, 1995;present study). The maintenance coefficients of 0.087 and 0.099/h reported in B. sphaericus (measured using total cell retention cultures) (Sachidanandham and Kalaiselvi, 1998) and B. thuringiensis (using chemostat) (Sachidanandham et al, 1997), respectively, were much lower than the value of 0.336/h observed in the present study in hyperosmotic complex substrate cultivations. In comparison, K90 exhibited a much lower maintenance coefficient, hence proving it to be better suited for complex substrate cultivations.…”

Section: Discussioncontrasting

confidence: 80%

“…However, mathematical modeling has significantly accelerated the bioprocess design of microorganisms (Bailey, 1998;Lessard, 1996), with a focus on the maintenance requirements of bacterial systems (Heijnen and VanDijken, 1992;Pirt, 1982;Scholten and Conrad, 2000;Thauer et al, 1977;Tijhuis et al, 1993;Traore et al, 1983). Maintenance requirements have been demonstrated even in phosphate limited cultures (Oh et al, 2000) as well as cultures which have been stoichiometrically well defined (Neijssel and Tempest, 1976;Stouthamer et al, 1990;van-Verseveld et al, 1986), for example, using a cell-recycle-system (San-Martin et al, 1994), continuous cultures (Becker and Maerkl, 2000;Mignone and Avignone-Rossa, 1996;Sachidanandham et al, 1997), total-cell-retention-cultures (Sachidanandham and Kalaiselvi, 1998) and under thermodynamic considerations (Scholten and Conrad, 2000). Therefore, maintenance requirements in bacteria, including B. thuringiensis, are a wasteful conversion of substrate, and should not be neglected.…”

Section: Introductionmentioning

confidence: 97%

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A crypticBacillusisolate exhibited narrow 16S rRNA gene sequence divergence withBacillus thuringiensisand showed low maintenance requirements in hyper‐osmotic complex substrate cultivations

Sachidanandham

Al-Shayji

Al-Awadhi

et al. 2005

Biotech & Bioengineering

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A cryptic Bacillus (K90) isolate obtained from soil samples from the Kuwait desert exhibited lower maintenance requirements in complex substrate cultivations than Bacillus thuringiensis. A mathematical model was used to estimate apparent maintenance coefficients (m(c)) and these were found to be 0.336 and 0.041/h for B. thuringiensis and K90, respectively. The results also showed that the values of apparent maintenance coefficients were inversely related to the specific growth rates. Furthermore, 16S rRNA gene sequencing showed that K90 exhibited 99.81% sequence similarity to that of B. mojavensis and 92.9% with B. thuringiensis. It is evident from the dendrogram that the evolution of B. mojavensis (K90) (B. subtilis group), which may have originated after B. licheniformis could have been influenced by prolonged hyper-osmotic conditions, while B. thuringiensis that evolved before B. oleronius exhibited greater sensitivity as implied by the higher maintenance coefficient obtained for the hyper-osmotic cultures. As K90 exhibited low maintenance requirements in hyperosmotic cultures, close phylogenetic relationship with B. thuringiensis, along with the reported property of encapsulation of insecticidal crystal proteins (Cry) in Bacillus strains and endophytic nature of B. mojavensis, strongly suggest that K90 could be a promising surrogate host for the transgenic delivery of "Cry" proteins.

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Section: Discussioncontrasting

confidence: 80%

Section: Introductionmentioning

confidence: 97%

A crypticBacillusisolate exhibited narrow 16S rRNA gene sequence divergence withBacillus thuringiensisand showed low maintenance requirements in hyper‐osmotic complex substrate cultivations

Sachidanandham

Al-Shayji

Al-Awadhi

et al. 2005

Biotech & Bioengineering

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“…In addition, it also exhibits maintenance requirement under unbalanced growth conditions. However, addition of amino acids increased the stability and reduced the maintenance requirements in steady state continuous cultures [7,8] which clearly implies that the B. sphaericus 1593M might require some other important growth factor(s). Appropriate supplementation of a correct growth factor might reduce the maintenance requirements.…”

Section: Estimation Of Maintenance Coefficientmentioning

confidence: 99%

Maintenance requirements in Bacillus sphaericus 1593M under dual substrate limitations estimated at zero growth rate in a total cell retention culture

Sachidanandham¹,

Kalaiselvi²

1998

Bioprocess Engineering

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The maintenance requirement(s) exhibited by Bacillus sphaericus 1593M was clearly established from the data on the steady state continuous cultures wherein the growth yield was found to be increasing with increase in dilution rate (4). In the present study we have attempted to estimate the maintenance coef®cient of B. sphaericus 1593M by achieving zero growth rate in a total cell retention culture (TCRC). Zero growth rate was achieved at a cell density of 5.57 g l A1 which remained constant reecting a steady state in the TCRC. Based on the substratē ux calculations, maintenance coef®cient was found to be 0.087 h A1 . Further, using this data of maintenance coef®-cient, steady state cell density and substrate pro®les in continuous cultures of B. sphaericus 1593M were predicted by simulation, which showed a close relationship to that of the experimental data.

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“…It has been realized that the optimum growth temperature of this organism was found to be lower than the temperature required for the product formation. It has been reported with B. thuringiensis that by appropriate supplementation of growth factors would reduce the maintenance requirement and improve the stability of the organism signi®cantly [14,13]. However, in the present case the bio-energetic relationship between growth and product formation need to be understood to get an insight into the maintenance metabolism of this organism.…”

Section: Effect Of Temperaturementioning

confidence: 99%

Mathematical model based estimation of volumetric oxygen transfer coefficient(s) in the production of proteolytic enzymes in Bacillus amyloliquefaciens

Sachidanandham

Kumar

Krishnan

et al. 1999

Bioprocess Engineering

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Alkaline protease is a class of important hydrolytic enzymes having wide applications in bioprocess industries. Their optimum pH in the alkaline range and stability at higher temperatures make them ideal in detergent and leather processing industries. These enzymes have excellent depilating capacity. The present study aims at process optimization for the production of alkaline protease from Bacillus amyloliquefaciens ATCC 23844. Information on the optimal operating temperature and pH were elicited from speci®c growth rates and alkaline protease yields. It was also observed that besides pH and temperature, the oxygen transfer rate is another important limiting variable for the production of protease. Volumetric oxygen transfer coef®cient (k L a) was estimated at various impeller speeds and aeration rates. The optimal impeller speed and aeration rates were determined from k L a and the relative protease yield data. It was understood that the oxygen transfer rate is one of the crucial parameters for the production of proteolytic enzymes by B. amyloliquefaciens. List of symbols mkinematic viscosity of the culture broth (m 2 s A1 ) g dynamic viscosity of the culture broth (kg s A1 m A1 ) q density of the culture broth (kg m A3 ) g acceleration due to gravity (m s A2 ) P energy transferred per time unit from the stirrer to the¯uid (N m s A1 ) V volume of the culture (m 3 ) F volumetric gas¯ow rate (m 3 s A1 ) D vessel diameter (m) k L a volumetric oxygen transfer coef®cient (h A1 ) B gasi®cation parameter (dimensionless) (P g /V) Ã power parameter (dimensionless) k L a Ã mass transfer parameter (dimensionless)

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Stabilization and increased production of insecticidal crystal proteins of Bacillus thuringiensis subsp. galleriae in steady- and transient-state continuous cultures

Cited by 11 publications

References 13 publications

A crypticBacillusisolate exhibited narrow 16S rRNA gene sequence divergence withBacillus thuringiensisand showed low maintenance requirements in hyper‐osmotic complex substrate cultivations

A crypticBacillusisolate exhibited narrow 16S rRNA gene sequence divergence withBacillus thuringiensisand showed low maintenance requirements in hyper‐osmotic complex substrate cultivations

Maintenance requirements in Bacillus sphaericus 1593M under dual substrate limitations estimated at zero growth rate in a total cell retention culture

Mathematical model based estimation of volumetric oxygen transfer coefficient(s) in the production of proteolytic enzymes in Bacillus amyloliquefaciens

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