Degradation of Synthetic and Natural Textile Materials Using Streptomyces Strains: Model Compost and Genome Exploration for Potential Plastic-Degrading Enzymes

Abstract

Given the environmental significance of the textile industry, especially the accumulation of nondegradable materials, there is extensive development of greener approaches to fabric waste management. Here, we investigated the biodegradation potential of three Streptomyces strains in model compost on polyamide (PA) and polyamide-elastane (PA-EA) as synthetic, and on cotton (CO) as natural textile materials. Weight change of the materials was followed, while Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to analyze surface changes of the materials upon biodegradation. The bioluminescence-based toxicity test employing Aliivibrio fischeri confirmed the ecological safety of the tested textiles. After 12 months, the increase of 10 and 16% weight loss, of PA-EA and PA, respectively, was observed in compost augmented with Streptomyces sp. BPS43. Additionally, a 14% increase in cotton degradation was recorded after 2 months in compost augmented with Streptomyces sp. NP10. Genome exploration of the strains was carried out for potential plastic-degrading enzymes. It highlighted BPS43 as the most versatile strain with specific amidases that show sequence identity to UMG-SP-1, UMG-SP-2, and UMG-SP-3 (polyurethane degrading enzymes identified from compost metagenome). Our results showcase the behavior of Streptomyces sp. BPS43 in the degradation of PA and PA-EA textiles in composting conditions, with enzymatic potential that could be further characterized and optimized for increased synthetic textile degradation.

Keywords: Streptomyces; bioremediation; compost; degradation; genome analysis; polyamide; textile.

Figure 1

The appearance of Streptomyces sp. R1, Streptomyces sp. BPS43, and Streptomyces sp. NP10. (a) Incubated on MSF plates with FESEM images of Streptomyces sp. R1, Streptomyces sp. BPS43 and Streptomyces sp. NP10, respectively (at a magnification of 13,000$\times$). (b) Incubated on MSF plates, MSM medium plates with Impranil DLN^®-SD, and MSM medium plates with CMC plates.

Figure 2

Weight loss (%) of textile samples upon incubation in bioaugmented model compost: (a) PA, (b) PA-EA, and (c) CO. Macroscopic appearance of textile samples before and after burial: (d) PA materials buried for 12 months (nonaugmented; BPS43—compost augmented with Streptomyces sp. BPS43); (e) PA-EA samples buried for 12 months (nonaugmented; BPS43—compost augmented with Streptomyces sp. BPS43); (f) CO samples buried for 30 days (nonaugmented; NP10—compost augmented with Streptomyces sp. NP10).

Figure 3

FTIR spectra of textile materials acquired after burial tests: (a) 12 months of incubation for PA and PA-EA materials; (b) 60 days of incubation for CO materials.

Figure 4

FESEM images of: PA, PA-EA, and CO textile samples (a) before burial; (b) in nonaugmented model compost; (c) in augmented model compost (at a magnification of 500$\times$ with the corresponding inserted images at a magnification of 5000$\times$).

Figure 5

(a) Inhibition of A. fischeri bioluminescence upon exposure to PA, PA-EA, and CO extracts (average ± the SD, and the comparison to the untreated control and a reference compound ZnSO₄ × 7H₂O). (b) Cytotoxicity of PA, PA-EA, and CO extracts towards HaCaT cell line (* = p ≤ 0.05).

Figure 6

(a) Phylogenetic tree showcasing the evolutionary relationship between Streptomyces sp. R1, S. spectabilis BPS43, S. rubiginosohelvolus NP10, and reference Streptomyces spp. (b) The total number of PA, PU, and CO degrading enzymes found in three Streptomyces genomes. (c) Phylogenetic tree of PA-degrading and PU-degrading enzymes extracted from Streptomyces sp. R1, S. spectabilis BPS43 and S. rubiginosohelvolus NP10 (presented as enzyme class based on InterProScan predictions: yellow area (Amidases-Amd); red area (Peptidases-Pep); purple area (Hydrolases-Hyd); and blue area (PETases and Esterases-Est)).