Related Experiment Video
Updated: Aug 9, 2026
07:24
Production of Chemicals by Klebsiella pneumoniae Using Bamboo Hydrolysate as Feedstock
Published on: June 29, 2017
PHA (polyhydroxyalkanoate) production potential of activated sludge treating wastewater
H Takabatake1, H Satoh, T Mino
1Dept. of Civil Engineering, Tohoku University, 06 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8579, Japan.
Summary
Wastewater sludge can convert organic pollutants into valuable biodegradable plastics called polyhydroxyalkanoates (PHAs). While sludge showed PHA production potential, current levels require further improvement for practical application in waste recovery.
Area of Science:
- Environmental Microbiology
- Polymer Science
- Waste Management
Background:
- Wastewater treatment systems primarily remove organic pollutants.
- Recovering organic pollutants as valuable materials, such as biodegradable plastics, is highly desirable.
- Polyhydroxyalkanoates (PHAs) are biodegradable plastics that can be synthesized from organic pollutants.
Purpose of the Study:
- To evaluate the potential of activated sludge from Tokyo wastewater treatment plants to produce polyhydroxyalkanoates (PHAs).
- To determine factors influencing PHA accumulation in activated sludge.
- To assess the feasibility of recovering organic pollutants as biodegradable plastics.
Main Methods:
- Collected 18 activated sludge samples from 4 wastewater treatment plants in Tokyo, Japan.
- Conducted aerobic batch experiments using excess acetate as the sole carbon source.
- Quantified PHA accumulation as a percentage of dry cell weight.
Main Results:
- Activated sludge samples accumulated PHA up to an average of 18.8% of dry cell weight (range: 6.0% to 29.5%).
- Maximum PHA content was more dependent on influent characteristics than operational conditions.
- Conventional activated sludge demonstrated PHA production capabilities comparable to anaerobic-aerobic activated sludge.
Conclusions:
- Activated sludge possesses the capability to accumulate significant amounts of PHA.
- Influent composition is a key factor influencing PHA production.
- Current PHA content levels necessitate further research and optimization for practical application in waste valorization.
Related Concept Videos
01:26Microbial Bioremediation of Hydrocarbons
Bioremediation is an environmentally sustainable process that employs living organisms—primarily microorganisms—to degrade or neutralize pollutants from contaminated environments. In oil spills and hydrocarbon pollution, bioremediation involves the use of hydrocarbon-degrading bacteria to transform toxic compounds into less harmful substances. This approach leverages natural microbial metabolic processes and is considered both cost-effective and ecologically favorable compared to physical or...
01:25Production of Organic Acids
Lactic acid, an important organic acid extensively applied in food, pharmaceutical, and biodegradable polymer industries, is primarily produced via microbial fermentation. This method is favored over chemical synthesis due to its environmental sustainability and capacity for enantiomerically pure product formation. Among various microbial processes, the fermentation of starch-based substrates stands out due to the abundance and renewability of raw materials like corn and potatoes.Hydrolysis of...
01:27Bioplastics
Bioplastics derived from microbial processes present a sustainable alternative to conventional petroleum-based plastics. Among these, polyhydroxyalkanoates (PHAs), particularly polyhydroxybutyrates (PHBs), have emerged as prominent candidates due to their biodegradability and biocompatibility. These polymers are synthesized by a variety of bacteria, such as Cupriavidus necator and Pseudomonas putida, which naturally accumulate PHAs as intracellular carbon and energy reserves, especially under...
01:30Biological Treatment of Effluent and Waste Water
Biological wastewater treatment relies on the metabolic activity of microorganisms to remove pollutants from sewage. In modern treatment systems, this process is organized into sequential stages that progressively reduce solid material, dissolved organic matter, and microbial contamination. Each stage plays a distinct role in improving water quality and preparing the effluent for safe discharge or reuse.Primary and Secondary TreatmentPrimary treatment is a physical process that removes large...
01:25Biofuels
The microbial conversion of organic matter into biofuels holds potential as a renewable energy source. Among biofuel sources, microalgae are recognized as a highly efficient and adaptable feedstock for biodiesel production, owing to their rapid biomass accumulation, elevated lipid productivity, and capacity to proliferate in diverse aquatic systems, including freshwater, marine, and wastewater habitats. Unlike terrestrial crops, microalgae do not compete for land and can achieve significantly...
01:28Microbial Bioremediation of Plastics
Polyethylene terephthalate (PET) is a synthetic polymer widely utilized in the packaging industry, particularly for bottles and containers. Due to its chemical stability and durability, PET accumulates in the environment, contributing significantly to plastic pollution. It comprises repeating units of terephthalic acid and ethylene glycol, resulting in a semi-crystalline structure that is resistant to natural degradation processes.A notable breakthrough in plastic biodegradation came with the...