Can bioplastics successfully decompose in Subarctic Latitudes?
Researchers of Siberian Federal University conducted a series of studies devoted to how soil bacteria and fungi decompose and digest special biopolymers produced at a pilot plant of Siberian Federal University. In particular, an article published in Chemosphere reports that the Krasnoyarsk researchers were the first in the world to study the ability of the microbial community inhabiting the soil of Evenkia to metabolize bioplastic.
“Microorganisms inhabiting the Evenk soils slightly differ in species composition from those that live to the south. However, they are very slow due to low temperatures, and their metabolic processes are inhibited. We studied how quickly these microorganisms are capable of degrading bioplastics based on polyhydroxyalkanoates (PHA), various types of which are produced at the university,” said Svetlana Prudnikova, co-author of the study, professor of the specialised department of biotechnology.
The tests at the Evenk department of the Institute of Forest Health (Siberian Branch of the Russian Academy of Science) were a continuation of the long-term research carried out by the staff of the department. Previously, the Krasnoyarsk researchers studied the similar behaviour of bacteria and fungi inhabiting the soils of the forest zone of Krasnoyarsk Territory, tested microscopic inhabitants of fresh and salty water bodies for destructiveness against biopolymers, and even studied the ability to process bioplastics in tropical bacteria inhabiting the soil of Vietnam.
“In the middle zone and, especially, the subtropics, the destruction of PHA-biopolymers is much faster. In the Evenk soils, however, we found a fairly diverse microbial community, which also copes with this task. The studied samples contain Bacillus pumilus — a bacterial strain which is widespread in soil, water bodies, and on plant roots. Other inhabitants of the permafrost include Pseudomonas, Variovorax, Rhodococcus — the bacteria known for their ability to destroy organic pollution in soils. As for the microscopic fungi in these latitudes, the most widespread are mould fungi — Aspergillus and Penicilliums. This microbiome is more than enough for high-quality processing of bioplastics,” the researcher continued.
The issue of soil pollution in the Far North remains highly urgent. The fragility and vulnerability of northern ecosystems and the long periods of restoration of local nature after cataclysms are evidenced, among other things, by the findings of scientists from the Siberian Branch of the Russian Academy of Sciences who are working to eliminate the consequences of the environmental disaster in Norilsk in May 2020. The studies of the SibFU bioengineers had been carried out long before the Norilsk events in Evenkia, but the conclusions obtained are quite versatile: if we tune the production of containers, packaging, and medical products from the biopolymers (the safety of which for vulnerable northern soils has been proved by the Krasnoyarsk specialists) developed by the SibFU pilot plant, this will partially solve the problem pollution of the subarctic and arctic zones of Russia.
“Along with soil temperature, moisture, the specific composition of local microflora, and the shape of a bioplastic product are of great importance for the biodegradation. In the Evenk experiment, particularly, we used thin PHA-films. The most important thing is the experimentally proven ability of cryogenic soils to absorb bioplastics without harmful effects on the environment, which, I hope, will replace a significant share of synthetic plastic on the market in the future,” concluded Svetlana Prudnikova.