Preparation of biodegradable plastic mulch from tannery raw trimming waste for sustainable agroecosystem

Biodegradable film is considered as a promising alternative to polyethylene film, which has caused many negative effects, such as environmental pollution and land degeneration. This study involves the enzymatic extraction of collagen from tannery solid waste (raw trimmings) yielding 21.5 % with a protein content of 63.38 %, and hydroxyproline content 16.68 %. Biodegradable films were prepared from various amount of collagen and rice starch in glycerin. Neem infused oil, extracted from neem leaves were added to the films at a concentration of 2–4 wt%, to provide insecticidal activity, potentially serving as natural pesticides for sustainable agriculture. Among the formulations the film S4 with a collagen-to-starch ratio of 1:3, exhibited the highest tensile strength 1.72 MPa due to intermolecular hydrogen bonding. Neem oil was added to S4 to induce insecticidal properties. The film produced from formulation S4–4 having 4 % neem oil showed water vapor transmission rate of 7.91 g/m 2 /h, and water solubility of 38.66 %, and 50 % degradation in soil after two weeks- comparable to other films. Most importantly S4–4 showed significantly higher insect mortality (12.8 %) after 3 h than control film (2.67 %) with mulching, even though neem oil did not affect the film properties. When applied to okra plants, the film prepared from S4–4 resulted in increased plant length (33.86 cm), root length (10.5 cm), and fresh and dry weight of the plants. The validity of the ANOVA models for each growth parameter confirmed that mulch treatment had a significant impact on plant growth, with S4-4 showing the best performance among all treatments, as the assumptions of normality, homoscedasticity, and independence were satisfied. Images of okra plants showed that those treated with S4-4 experienced less leaf damage compared with plants treated with other biodegradable films or commercial mulch.