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Vikash

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Its a presentation describing how thermophillic bacteria grow in continuous culture. …

Its a presentation describing how thermophillic bacteria grow in continuous culture.
It consists basic information about continous culture and two research papers.

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  • 1. -by Vikash Shashi Veer Kumar Ajay Kumar Mr Meena Bhawani Shankar
  • 2. Bacterial Growth o most lab organisms are grown in a batch culture  closed system  new materials are not added  waste products are not removed  under these conditions bacteria populations follow distinct patterns of growth. Algae batch cultures
  • 3. Continuous Culture  continuous culture is maintained by-  nutrients must be continually supplied  end products must be removed  exponential growth phase maintained Continuous culture in lab
  • 4. Growth in Batch Culture  “Growth” is generally used to refer to the acquisition of biomass leading to cell division, or reproduction.
  • 5. Bacterial Growth Curve: laboratory conditions  bacterial growth generally follows a characteristic pattern  4 phases  normal growth curve, with optimum environmental and nutritional conditions
  • 6. Bacterial Growth Curve: laboratory conditions  lag phase  no increase in cell numbers  cells are adapting to the environment  cells are preparing for reproduction synthesizing new DNA, etc.
  • 7. Bacterial Growth Curve: laboratory conditions  log phase  exponential phase  maximal rate for reproduction this happens with a specific set of growth conditions those resources for growth are abundantly available
  • 8. Bacterial Growth Curve: laboratory conditions  stationary growth phase  maximum population for the resources available required nutrients become depleted inhibitory end products from cell metabolism accumulate  cell growth = cell death
  • 9. Bacterial Growth Curve: laboratory conditions  death phase  cell death > new cell formation
  • 10. Growth Kinetics and Yield Coefficients of the Extreme Thermophile Thermothrix thiopara in Continuous Culture Daniel K. Brannan and Douglas E. Caldwell
  • 11. Continuous culture studies were carried out at three temperatures (65, 70, and 75°C) with a culture volume of 350 ml, provided with agitation (200 rpm). Temperature was accurately regulated with rheostat-controlled heat tapes and a thermostatically controlled heating element. Aeration was provided by controlling the flow rate (350 cm3/min) of air enriched with 5% (vol/vol) C02, using a Manostat flow meter .The culture pH remained constant (6.7 ± 0.2) during steady states. Wall growth was minimized by coating the culture vessel with 5% (vol/vol) dichlorosilane.
  • 12. Determination of μ-max by washout kinetics The maximum specific growth rate (μ-max) was determined by washout kinetics . During washout, cells were counted at 0.5-h intervals over 4 h, using a Petroff- Hauser bacterial counter. Cell numbers were also determined by absorbance at 460 nm, using a cell number-absorbance calibration curve.
  • 13. The equations of Marr et al. and Pirt were used to account for substrate used for growth and maintenance, where maintenance is the consumption of potential biomass- μX/Y=μX/YG +aX/YG -(1) Where, μ = specific growth rate, X = biomass, Y = actual or observed yield, YG = theoretical growth yield (yield corrected for maintenance), a = specific maintenance rate, and m = maintenance coefficient = a/YG. Determination of growth efficiency (Eg)
  • 14. When μ = μmax, the equation becomes: μ –maxX/Y = μ–maxX/YG + aX/Y; -(2) Thus, the total rate of substrate utilization at μ max (μ maxX/YT) equals the rate used for growth (μ-maxX/YG) plus that used for maintenance (aX/YG). The fraction (F) of substrate used for growth at μ -max is: F = (μ –max X/YG)(μ-maxX/Y) -(3) Substituting for μ-maxX/Y from equation (2) results in the following ratio: F = (μ –max X/YG)/[μ–maxX/YG + aX/Y] -(4) By cancelling terms and defining F as the growth efficiency, the following equation is obtained: Eg = μ-max/(μ-max + a). Growth efficiency (Eg) can then be determined from μ -max and the specific maintenance rate (a).
  • 15. RESULTS AND DISCUSSION The Eg for T. thiopara at 70°C indicates that 84% of the theoretical growth yield was attained (Table 1). Literature values were used to obtain a, Ymax, YG, and Eg for other organisms grown under a variety of conditions (Table 2). The growth efficiency of T. thiopara at μ -max (0.84 h-1) was lower than those of Thiobacillus ferroxidans (0.94 h-1) and Thiobacillus dentrificans (0.94 h-1) but greater than that of Thiobacillus neapolitanus (0.60 h-1 ). The lower growth efficiency of T. thiopara was due to its higher specific maintenance rate (a).

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