Promoting Fertilizer Use via Controlled Release of a Bacteria-Encapsulated Film Bag

Abstract

A phosphate-solubilizing bacterium ( Burkholderia cepacia isolate) encapsulated in maleic anhydride (MA) grafted onto poly(butylene succinate adipate) (PBSA) and then combined with starch as film bag material (PBSA-g-MA/starch) incubated in a saline solution required approximately 20 days to deplete the starch in the film bags. Thereafter, the cell concentration in the saline solution increased significantly because of the release of cells from the severely destroyed film bags and also their growth by use of depolymerized PBSA-g-MA fragments as a substrate. The incubation proceeded for 60 days, by which time the PBSA-g-MA/starch composite had suffered a >80% weight loss. For practical application, effectiveness of the above-mentioned film bags was demonstrated because it could improve the absorbability of a fertilizer for plants and promote the growth of plants. As a result, it can avoid the accumulation of the phosphate in excess fertilizer that lead to the phenomenon of poor soils. These results demonstrate that PBSA-g-MA/starch can be used to encapsulate cells of an indigenous phosphate-solubilizing bacterium ( B. cepacia isolate) to form a controlled release of bacteria-encapsulated film bag (BEFB). The B. cepacia isolate was able to degrade the film bags material, causing cell release. Biodegradability of the film bags depended upon the type of material used, because the PBSA film bags were also degraded but to a lesser degree. The addition of starch made the film bags more biodegradable. The decrease in intrinsic viscosity was also higher for the starch composite, suggesting a strong connection between the biodegradability and these characteristics. The results suggest that the release of fertilizer-promoted bacteria might be controllable via a suitable film bag material formulation. In addition, this work adopted live bacteria to promote the absorption of phosphate, which is superior to the phosphate used in the traditional way.

Accelerated Biodegradation of Agriculture Film Based on Aromatic–Aliphatic Copolyester in Soil under Mesophilic Conditions

“…It has recently been demonstrated that the biodegradation of PBAT under mesophilic conditions is a slow process, taking many months, and higher levels of mineralization are difficult to achieve. ,, For example, in the work by Rychter et al, 15% weight loss was recorded after 10 months of incubation at 30 °C . Developing PBAT-based materials with improved biodegradation under mesophilic conditions in soil would help to achieve decomposition of disused films, e.g., mulching films, in situ , and, hence, decrease expenses connected with collecting and composting of the material. ,, Another advantage could be an eventual positive effect on crops and soil structure or the possibility of incorporating fertilizers or plant protection agents. ,− …”

Controlled-Release Fertilizer Prepared Using a Biodegradable Aliphatic Copolyester of Poly(butylene succinate) and Dimerized Fatty Acid

“…This material was shown to be biodegradable in biodegradation tests carried out on thin polymer films (60 × 60 × 0.5 mm) under controlled conditions at 50 °C for 3 months in a mixture of sand and compost, according to the previously reported procedure . The weight losses of the PBS/DLA copolyester were approximately 5 wt % after 1 month, 8 wt % after 2 months, and 10 wt % within 3 months of incubation; however, there are reports on complete biodegradation of PBS and PBS blends with various organic materials. ,, …”

“…26 The weight losses of the PBS/DLA copolyester were approximately 5 wt % after 1 month, 8 wt % after 2 months, and 10 wt % within 3 months of incubation; 25 however, there are reports on complete biodegradation of PBS and PBS blends with various organic materials. 22,23,27 Despite the fact that the use of PBS/DLA in the preparation of controlled-release fertilizers may bring many benefits, especially in the context of environment protection, it should be kept in mind that PBS is not a cost-effective material. The price of commercially available PBS is approximately 5.4−5.6 euro/kg, and it is comparable with other synthetic biodegradable polyesters 28 but slightly higher than the price of biobased, biodegradable polymers from natural resources and several times higher than the price of conventional, not biodegradable synthetic polymers.…”

“…The objective of this research was to obtain materials with controlled-release properties by coating granules of a mineral fertilizer with a layer of biodegradable aliphatic copolymer of poly(butylene succinate) and a butylene ester of dilinoleic acid (PBS/DLA) using an immersion method, to characterize the prepared materials, and to evaluate the nutrient release kinetics. As far as we know this kind of copolyester (PBS/DLA) has not been used in the preparation of controlledrelease fertilizer; however, copolyesters of succinic acid with starch 22 and maleic anhydride 23 have been evaluated as biodegradable matrix materials for the controlled release of bacterial fertilizers.…”

Mussel-Inspired Thermosensitive Polydopamine-graft-Poly(N-isopropylacrylamide) Coating for Controlled-Release Fertilizer

“…Fertilizers have been used to supply nutrients in growing media for many years, and they are added to soil to supply one or more plant nutrients essential to the growth of plants. , However, the nutrients of a common fertilizer is lost to the environment easily and cannot be abundantly taken up by plants, which results in the contamination of water, air, etc . An effective way to improve nutrient use efficiency while reducing the environmental hazards is using slow- or controlled-release fertilizers (SCRFs), contributing to the sustainable development of agriculture and the environment. − In comparison to traditional fertilizers, SCRFs have many advantages.…”