Biodegradation Efficiency of Pla in Microbial Windrow Composting System with Organic and Invasive Species Waste

Abstract

The rapid accumulation of plastic waste and invasive plant biomass poses serious environmental challenges in terrestrial and aquatic ecosystems. Biodegradable biopolymers such as polylactic acid (PLA), along with invasive weeds including Water hyacinth, Parthenium hysterophorus, Saccharum spontaneum, and Ipomoea carnea, generate substantial organic residues that are often poorly managed. This study evaluated the efficiency of windrow heap co-composting of invasive weed biomass and PLA biopolymer blended with vegetable waste and cow dung to produce nutrient-enriched organic fertilizer. Composting was conducted for 56 days under controlled aeration and moisture conditions with periodic turning. Changes in physicochemical parameters including temperature, moisture content, pH, electrical conductivity (EC), total organic carbon (TOC), C/N ratio, ash content, volatile organic compounds (VOCs), and macronutrients (N,P,K) were monitored. Microbial succession was assessed through culture-dependent isolation, biochemical profiling, and 16S rRNA gene sequencing. Results demonstrated rapid thermophilic activity during the initial phase, followed by stabilization and maturation, with final C/N ratios declining to 10–11.5, indicating compost maturity. Treatments containing moderate PLA (20–30%) and Parthenium biomass showed enhanced organic matter degradation and superior nutrient enrichment. Molecular identification revealed dominant bacterial taxa affiliated with Aeromonas caviae and Enterobacter hormaechei, highlighting active heterotrophic communities during biodegradation. The study demonstrates that windrow co-composting of invasive weeds and PLA biopolymer with organic wastes is an effective, scalable strategy for sustainable waste management, invasive species valorization, and production of high-quality organic fertilizer suitable for agricultural application.