Development of a bio-based composite from <i>in situ</i> extracted neem oil, threadlets, and <i>Bacillus</i> sp. PhNs9 synthesized PHBV utilizing sugarcane molasses

Environmental concerns over synthetic plastics highlight the need for sustainable alternatives, among which bacterial polyhydroxyalkanoates (PHAs) have emerged as promising. However, their commercialization is limited, owing to their higher production cost and lower applicability. Hence, this study employs ANN-GA-based optimization of a novel <i>in-situ</i> fed-batch process using a self-isolated <i>Bacillus</i> sp. PhNs9 utilizing untreated sugarcane molasses as a cost-effective substrate. The bioreactor scale production at optimized conditions resulted in a PHA production of 3.47 ± 0.11 g/L, whose GC-MS and DSC analysis revealed it to be Polyhydroxybutyrate-co-valerate (PHBV). This PHBV was successfully blended with <i>in-situ</i> extracted neem oil and threadlets to form a biocomposite, which was found to be antibacterial, non-cytotoxic, and biodegradable with significantly higher tensile strength. The HR-MS analysis of the extracted neem oil revealed the presence of bioactive compounds like nimbin, azadirachtin, and Salannin, providing medicinal properties. The techno-economic analysis of the whole process resulted in the cost of PHBV production and extraction as ₹1.03/g, extraction of neem oil as ₹5.75/mL, which further resulted in the biocomposite preparation cost to be ₹0.30 cm^-2. This accentuates the commercial feasibility of the developed biocomposite as an eco-friendly alternative to synthetic plastics.