A team of scientists from Saigon University isolated two strains of microorganisms found in paper mill sludge to create bioplastics.
The research, conducted by Dr. Ho Ky Quang Minh, a lecturer in the environmental science department, and 10 colleagues since 2020, aims to create biodegradable plastics that can decompose within 30 days. The project also focuses on recycling waste into useful raw materials according to the circular economy model.
According to Dr. Minh, wastewater (including sludge) from paper mills, seafood processing plants, sugarcane processing plants, etc., contains many organic substances. Although this wastewater environment is quite harsh and contains many toxins, microorganisms can completely adapt to synthesize and accumulate a type of polymer (bioplastic) within their bodies.
The research team used water and sludge samples from a paper mill in Tien Giang province to analyze the microbial strains in the environment. Through isolation, identification, and exclusion of potentially pathogenic bacteria, the team found more than 100 microbial strains capable of producing bioplastics.
Analyzing their biological characteristics, the team evaluated two bacterial strains, Bacillus pumilus (NMG5) and Bacillus megaterium (BP5), as having the best plastic production efficiency. "Among the bacterial strains we isolated, there is still the potential for more strains with higher efficiency," said Dr. Minh. Laboratory results showed that these two bacterial strains accumulated 40% of their dry weight as bioplastic.
Testing the biodegradability of bioplastic (white) in the environment. Photo: Provided by the interviewee .
The paper mill in Tien Giang has a wastewater treatment capacity of approximately 30,000 m3 per day, of which 30% is sludge, or about 10,000 m3. The research team calculated that, theoretically, about 40 tons of bioplastics could be obtained from microorganisms. However, Dr. Minh believes that even if the amount of bioplastics obtained is only half of the theoretical calculation, it is still a very large difference.
Analysis shows that microorganisms present in the factory's wastewater sludge utilize organic matter in the environment as food, thus possessing the ability to purify water. Therefore, the team proposes the development of activated sludge blocks that simultaneously produce bioplastics and treat water more effectively. To obtain the bioplastics, chemical or physical methods must be used to break down the cell walls of the microorganisms, which are typically composed of polysaccharides. Then, a solvent is used to precipitate the bioplastics. These bioplastics, when present in the environment, serve as a food source for surrounding microorganisms, leading to rapid decomposition.
The research team collaborated with the paper mill to collect water and sludge samples for the study. Photo: Provided by the team.
Mr. Truong Minh Tri, Director of SG Workspace, a company specializing in environmental investment and sustainable development, said that the use of microorganisms to create bioplastics and treat wastewater has been researched in many developed countries, with some having applied it on an industrial scale. In Vietnam, there have been some studies on bioplastics for use in environmental protection, agriculture, etc.
According to Mr. Tri, the trend of recycling products to protect the environment will become more widespread in the next 5-10 years. However, for recycled products made from waste to become popular and competitive in the market, they must meet quality and price requirements compared to traditional products. To achieve this, bioplastic products must be optimized to ensure quality and large-scale production must be built to reduce costs. Simultaneously, government policies need to introduce mandatory conditions to limit the use of traditional plastic bags, creating conditions for bioplastic products to penetrate the market more widely.
"With our team's project, we will continue to participate in laboratory-scale experimental stages to evaluate and coordinate with businesses to develop pilot production processes, and seek investment to bring the product to market soon," Mr. Tri said.
Ha An
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