AI SearchConversion of organic wastes into biodegradable plastic : polyhydroxyalkanoates (PHA)
Call Number: AIT Thesis no.EV-03-5 Material type:
SeriesSeries: Asian Institute of Technology. Thesis ; no. EV-03-5Publication details: Pathum Thani, Thailand : Asian Institute of Technology, 2003Description: 81 leaves : illSubject(s): Online resources: Dissertation note: Thesis (M.Eng.) - Asian Institute of Technology, 2003 Summary: In the present study, preliminary trial was made to produce biodegradable plastic material polyhydroxyalkanoates (PHAs) by using a special group of microorganisms called glycogen-accumulating organisms (GAOs) in activated sludge. The most unique point about GAOs is their ability to convert glucose into PHAs under anaerobic condition. In the first phase of the study, screening of activated sludgewith high GAOs activity was conducted. Three different activated sludge samples were taken and compared about the activity of GAOs. The activity of GAOs was measured as the activity of the sludge to be tested to convert glucose into PHA under anaerobic conditions. The results showed that only the sludge taken from Starch WWTP accumulated PHA from glucose significantly under anaerobic conditions. In the second phase of the study, a laboratory scale sequencing batch reactor was operated under the sequencing anaerobic-aerobic conditions with glucose as the main carbon substrate in order to enrich GAOs. The activated sludge from the starch WWTP was selected as the seed sludge. The GAOs activity was weekly determined by anaerobic batch experiment with glucose as the feed. As the result of the enrichment, GAOs activity in sludge increased about four times. In addition, amount of PHA production from acetate under aerobic condition was also strengthened about four times .. In the last phase of the study, effect of substrate concentration on PHA production from glucose under anaerobic condition and from acetate under aerobic condition was investigated. Two various glucose concentrations (800 mgC/l and 1200mgC/l) was used to investigate the PHA production capacity of selected activated sludge. 3HV rich PHA was accumulated with the increase of glucose consumption. The PHA conversion rate was around 0.5. Large amounts of glucose taken up could be used for other metabolic activities of microorganisms other than PHA production. Two different acetate concentrations ( 480 mgC/l and 9600 mgC/l) were compared in relation to PHA production. Sludge of 960mgC/l acetate exhibited better PHA production capacity than the sludge added with 480mgC/l acetate.
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Thesis (M.Eng.) - Asian Institute of Technology, 2003
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering.
In the present study, preliminary trial was made to produce biodegradable plastic material polyhydroxyalkanoates (PHAs) by using a special group of microorganisms called glycogen-accumulating organisms (GAOs) in activated sludge. The most unique point about GAOs is their ability to convert glucose into PHAs under anaerobic condition. In the first phase of the study, screening of activated sludgewith high GAOs activity was conducted. Three different activated sludge samples were taken and compared about the activity of GAOs. The activity of GAOs was measured as the activity of the sludge to be tested to convert glucose into PHA under anaerobic conditions. The results showed that only the sludge taken from Starch WWTP accumulated PHA from glucose significantly under anaerobic conditions. In the second phase of the study, a laboratory scale sequencing batch reactor was operated under the sequencing anaerobic-aerobic conditions with glucose as the main carbon substrate in order to enrich GAOs. The activated sludge from the starch WWTP was selected as the seed sludge. The GAOs activity was weekly determined by anaerobic batch experiment with glucose as the feed. As the result of the enrichment, GAOs activity in sludge increased about four times. In addition, amount of PHA production from acetate under aerobic condition was also strengthened about four times .. In the last phase of the study, effect of substrate concentration on PHA production from glucose under anaerobic condition and from acetate under aerobic condition was investigated. Two various glucose concentrations (800 mgC/l and 1200mgC/l) was used to investigate the PHA production capacity of selected activated sludge. 3HV rich PHA was accumulated with the increase of glucose consumption. The PHA conversion rate was around 0.5. Large amounts of glucose taken up could be used for other metabolic activities of microorganisms other than PHA production. Two different acetate concentrations ( 480 mgC/l and 9600 mgC/l) were compared in relation to PHA production. Sludge of 960mgC/l acetate exhibited better PHA production capacity than the sludge added with 480mgC/l acetate.
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