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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. 1. -by Vikash Shashi Veer Kumar Ajay Kumar Mr Meena Bhawani Shankar
  2. 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. 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. 4. Growth in Batch Culture  “Growth” is generally used to refer to the acquisition of biomass leading to cell division, or reproduction.
  5. 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. 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. 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. 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. 9. Bacterial Growth Curve: laboratory conditions  death phase  cell death > new cell formation
  10. 10. Growth Kinetics and Yield Coefficients of the Extreme Thermophile Thermothrix thiopara in Continuous Culture Daniel K. Brannan and Douglas E. Caldwell
  11. 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. 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. 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. 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. 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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