Biodegradation Studies of Polyhydroxybutyrate and Polyhydroxybutyrate- co-Polyhydroxyvalerate Films in Soil

Jihyeon Kim; Nevin S Gupta; Lindsey B Bezek; Jacqueline Linn; Karteek K Bejagam; Shounak Banerjee; Joseph H Dumont; Sang Yong Nam; Hyun Woo Kang; Chi Hoon Park; Ghanshyam Pilania; Carl N Iverson; Babetta L Marrone; Kwan-Soo Lee

doi:10.3390/ijms24087638

Biodegradation Studies of Polyhydroxybutyrate and Polyhydroxybutyrate- co-Polyhydroxyvalerate Films in Soil

Int J Mol Sci. 2023 Apr 21;24(8):7638. doi: 10.3390/ijms24087638.

Authors

Affiliations

¹ Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
² Department of Materials Engineering and Convergence Technology, Gyeongsang National University, Jinju 52828, Republic of Korea.
³ Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁴ Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁵ Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, Jinju 52725, Republic of Korea.
⁶ General Electric Global Research Center, Niskayuna, NY 12309, USA.

Abstract

Due to increased environmental pressures, significant research has focused on finding suitable biodegradable plastics to replace ubiquitous petrochemical-derived polymers. Polyhydroxyalkanoates (PHAs) are a class of polymers that can be synthesized by microorganisms and are biodegradable, making them suitable candidates. The present study looks at the degradation properties of two PHA polymers: polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-polyhydroxyvalerate (PHBV; 8 wt.% valerate), in two different soil conditions: soil fully saturated with water (100% relative humidity, RH) and soil with 40% RH. The degradation was evaluated by observing the changes in appearance, chemical signatures, mechanical properties, and molecular weight of samples. Both PHB and PHBV were degraded completely after two weeks in 100% RH soil conditions and showed significant reductions in mechanical properties after just three days. The samples in 40% RH soil, however, showed minimal changes in mechanical properties, melting temperatures/crystallinity, and molecular weight over six weeks. By observing the degradation behavior for different soil conditions, these results can pave the way for identifying situations where the current use of plastics can be replaced with biodegradable alternatives.

Keywords: biodegradable polymers; density functional theory; green chemistry; polyhydroxybutyrate; polymer degradation.

MeSH terms

Biodegradable Plastics*
Biodegradation, Environmental
Polyesters / chemistry
Polyhydroxyalkanoates* / chemistry
Soil

Substances

Polyesters
Soil
polyhydroxybutyrate
Polyhydroxyalkanoates
Biodegradable Plastics

Grants and funding

This work was supported by the U.S. Department of Energy through the Los Alamos National Laboratory. The Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001). Research presented in this article was supported by both the Laboratory Directed Research and Development program [Grant Number 20190001DR] and the Pollution Prevention Program of Los Alamos National Laboratory. This work was supported by the Korea Institute for Advancement of Technology (KIAT) with a grant funded by the Korea Government (MOTIE) (P0017310, Human Resource Development Program for Industrial Innovation (global).