Sustainable production of liquid phenyl using oil extracted from discarded pupae of mulberry silk worms (Bombyx mori)

Abstract

The mulberry silkworm (Bombyx mori) pupae, typically discarded as waste by the silk industry, are a valuable source of oil. Using the Soxhlet extraction method, 30.4 % oil was recovered from the pulverized dried pupae. This oil exhibited a high iodine value of 120 gI2/100 g and a saponification value of 201 mg KOH/g, which qualified it for soap making in phenyl. Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified five fatty acids in the oil: palmitoleic acid, linoleic acid, oleic acid, stearic acid, and palmitic acid. The composition was 38.80 % saturated fatty acids (SFA), 46.01 % monounsaturated fatty acids (MUFA), and 15.20 % polyunsaturated fatty acids (PUFA). A disinfectant liquid, phenyl, was formulated using this oil, leveraging its high oleic acid content (45.10 %) and favorable physicochemical properties. The antibacterial efficacy of the phenyl was tested against eight harmful bacterial strains. It showed significant activity against all tested bacteria, particularly gram-negative strains, with inhibition zones ranging from 20.25 to 28.0 mm, outperforming the positive control, chloramphenicol, which had inhibition zones of 15.45–19.40 mm. For gram-positive bacteria, the inhibition zones were 14.25–22.50 mm. The phenyl was most effective against Pseudomonas aeruginosa and Escherichia coli, with inhibition zones of 28.0 mm and 23.50 mm, respectively. The minimum inhibitory concentration (MIC) was highest for Pseudomonas aeruginosa and Escherichia coli at 110 μL/mL, and for Staphylococcus aureus at 115 μL/mL. The prepared phenyl disinfectant proved to be efficient against a range of bacteria and can be used to sanitize various surfaces effectively.