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Table 3 Effect of pH, temperature, carbon and nitrogen sources on production of polyhydroxybutyrate (PHB) by isolate AWW

From: Production of biodegradable plastic by polyhydroxybutyrate (PHB) accumulating bacteria using low cost agricultural waste material

Parameter/nutrient Dry biomass (g/l)* PHB (g/l) % PHB (w/w)
Temperature (°C)
 37 12 ± 0.12a 6.8 ± 0.12a 56.66a
 30 9.6 ± 0.21b 4.9 ± 0.21b 51.04b
 40 7.8 ± 0.02c 3.1 ± 0.00c 39.74c
 25 8.3 ± 0.09d 2.5 ± 0.02d 30.12d
pH
 7.0 12 ± 0.26a 5.2 ± 0.03a 55.00a
 7.5 11 ± 0.60b 5.1 ± 0.12a 51.00a
 6.5 10 ± 0.05c 2.9 ± 0.02b 29.00b
 8.0 9.5 ± 0.4c 2.6 ± 0.00c 27.36c
Carbon source
 Glucose 10.0 ± 0.02a 6.1 ± 0.07a 61.00a
 Sugarcane bagasse 9.0 ± 0.34b 5.0 ± 0.08b 55.55b
 Fructose 9.6 ± 0.06a 5.2 ± 0.11b 54.16b
 Corn cob 9.3 ± 0.09 b 4.8 ± 0.34b 51.61c
 Sucrose 8.6 ± 0.28 c 4.2 ± 0.13c 48.83c
 Teff straw 8.3 ± 0.21c 3.2 ± 0.26d 38.55d
 Banana peel 7.8 ± 0.00d 2.1 ± 0.03e 26.92e
Nitrogen source
 Peptone 8.2 ± 0.21a 5.2 ± 0.33a 63.41a
 Ammonium nitrate 8.0 ± 0.41a 4.1 ± 0.23c 51.25b
 Yeast extract 9.9 ± 0.03b 4.7 ± 0.02b 47.47b
 Sodium nitrate 9.6 ± 0.09b 4.3 ± 0.12c 44.79c
 Casein 8.7 ± 0.09c 3.5 ± 0.03d 40.22d
 Ammonium sulphate 7.6 ± 0.11d 3.0 ± 0.53e 39.47d
  1. Growth parameters were maintained at pH 7, 370 °C, 48 h and 150 rpm except for pH and Temperature tests
  2. * Biomass weight takes account of PHB weight
  3. Results are means of 2 trials done in triplicates ± standard deviation
  4. Different superscript letters indicate significant difference within the same column at P  <  0.05