Effect of biodegradable poly-3-hydroxybutyrate amendment on the soil biochemical properties and fertility under varying sand loads

Abstract

Background Poly-3-hydroxybutyrate (P3HB) is a bacterial intracellular carbon and energy storage polymer, used as a thermoplastic polyester in a wide array of industrial and agricultural applications. However, how the soil microbiome and fertility are altered by exogenously applied P3HB has been relatively unexplored. This study aimed to assess the effects of P3HB addition to nutrient restricted soil: its biological properties and lettuce (Lactuca sativa L. var. capitata L.) biomass production. The experiment was designed to evaluate impacts of spatial arrangement of the relatively organic-rich (soil organic matter, P3HB particles) versus poor fractions of the matrix with confounding factors such as variable microbial biomass, inherent nutrient/energy status, different water relations (due to variable hydrophysical properties of soil augmented by sand at different ratios). Results The results revealed that P3HB in soils induced inconsistent to contradictory changes in the microbial abundance as well as in most enzymatic activities. The differences were conditioned by the sand content both under P3HB presence or absence. On the other hand, dehydrogenase, urease activities, basal and substrate-induced soil respirations were mostly enhanced by P3HB addition, directly with increasing sand content (several respiration types). Nevertheless, P3HB significantly inhibited lettuce biomass production. Conclusions P3HB introduction to soil boosts the microbial activity owing to the preferential utilization of P3HB as C source, which depletes soil N and strongly inhibits the plant growth. Enhanced microbial activity in P3HB-amended soils with high sand content (60–80%) suggested that in nutrient-impoverished soil P3HB can temporarily replace SOM as a C source for microbial communities due to the shift of their structure to preferentially P3HB-degrading microbiome. Graphical Abstract

Effects of poly(3-hydroxybutyrate) [P(3HB)] coating on the bacterial communities of artificial structures

“…Different from previous studies that primarily used coatings to increase surface area for biofilm attachment [ 30 , 31 ], the P(3HB) coating functions differently by attracting bacterial communities. It achieves this by regulating the availability of limiting nutrients in the environment [ 78 , 79 ]. P(3HB) is known to be degraded by specific bacteria possessing P(3HB) degradation enzymes.…”

“…Non-P(3HB)-degrading bacteria may not have been able to penetrate or adhere effectively to the underlying concrete surface due to the denser coating, thus limiting their access and resulting in lower biofilm coverage. On the other hand, the thicker P(3HB) coating in the G-66 sample created a favourable environment for the growth and colonization of P(3HB)-degrading bacteria, giving them a competitive advantage over non-P(3HB)-degrading bacteria in the biofilm community [ 79 ]. This selective advantage led to a dominance of P(3HB)-degrading bacteria in the microbial community of the G-66 sample.…”

Sustainable Polyhydroxyalkanoate Production from Food Waste via Bacillus mycoides ICRI89: Enhanced 3D Printing with Poly (Methyl Methacrylate) Blend

“…It is noteworthy that controlling the soil beds' conditions, such as using 2% humus content, 24% water content, and a pH of 6.5, induced a microbially active environment optimal for biodegradation. The biodegradation of PHB is usually related to the microbial enzymatic action [70]. On the contrary, PMMA is an environmentally friendly non-biodegradable polymer whose biodegradability is enhanced through blending with other biodegradable polymers.…”

One-Pot Biosynthesis of Acetone from Waste Poly(hydroxybutyrate)

“…The plastic waste crisis has driven a rapid increase in the development and production of bioderived and biodegradable polymers, − and the combined “bioplastics” production capacity is now projected to grow from 2.2 million tonnes per year in 2022 to approximately 6.3 million tonnes per year by 2027 . With this, a sharp increase in the volume of post-consumer bioplastic waste is anticipated, prompting calls for mitigation of potential risks associated with its disposal through development of appropriate waste management technologies. − …”