A team of scientists from Saigon University isolated two strains of microorganisms present in the sludge of paper mills to create bioplastics.
The research has been carried out by Dr. Ho Ky Quang Minh, a lecturer in the environmental department, and 10 associates since 2020 with the goal of creating bioplastics that can decompose in 30 days. The project also aims to recycle waste into useful materials according to the circular economy model.
According to Dr. Minh, wastewater (including sludge) from paper mills, seafood, cane sugar... contains many organic substances. Although this wastewater environment is quite harsh and contains many toxins, microorganisms can fully adapt to the synthesis mechanism, accumulating a polymer (bioplastic) in the body.
The research team used water and sludge samples from a paper factory in Tien Giang to analyze microbial strains in the environment. By the methods of isolating, identifying and excluding potentially infectious bacteria, the group has resulted in more than 100 strains of microorganisms capable of creating bioplastics.
Analyzing biological characteristics, the team evaluated two strains of bacillus pumilus (NMG5) and bacillus megaterium (BP5) for the best resin production performance. "Among the bacterial strains we isolated, there are still likely to be many strains with higher efficiency," Dr. Minh said. The results of laboratory studies show that these two strains of bacteria have a ratio of 40% of the accumulated dry mass as bioplastic.
The paper mill in Tien Giang has a wastewater treatment capacity of about 30,000 m3 a day and night, of which 30% is sludge, or about 10,000 m3. The team calculated that about 40 tons of bioplastic could theoretically be obtained from microorganisms. However, Dr. Minh said that the case where the volume of bioplastics is only half of the theoretical calculation is also a very large percentage.
Through analysis, it was found that microorganisms exist in the sewage sludge of the factory and use food from organic matter in the environment, so they have the ability to clean water. Accordingly, the team proposes that it is possible to develop activated sludge blocks that both create bioplastics and treat water with better efficiency. To get the bioplastic, it will have to use chemical or physical measures to break down the cell walls of microorganisms, which are usually made of polysaccharides. Then use solvent for precipitation to obtain bioplastic. This plastic, when present in the environment, will be a food source for surrounding microorganisms, so it will decompose very quickly.
Truong Minh Tri, Director of SG Workspace Company specializing in environmental investment and sustainable development, said that using microorganisms to create bioplastics and treat wastewater has been developed by many countries. There are places where it has been applied on an industrial scale. In the country, there have been a number of studies on bioplastics serving in environmental protection, agriculture...
According to Mr. Tri, the trend of product recycling to help protect the environment is more popular in the next 5-10 years. However, products recycled from waste to be popular and competitive in the market must meet the quality and price requirements compared to traditional products. To achieve this requirement, bioplastic products must be optimized to ensure quality and build large-scale production to reduce costs. At the same time, state policies need to introduce mandatory conditions in limiting the use of traditional plastic bags, creating conditions for bioplastic products to penetrate the market more.
"With the project of our team, we will continue to participate in laboratory-scale experiments to evaluate and coordinate with businesses to build trial production processes, call for investment so that products can be released soon. market", Mr. Tri said.
Hà An - Vnexpress
