Evaluation of the Potential of Ricinus communis L (Castor) Seed as a Substrate for Biorefinery Applications

Abstract

The world is facing numerous ecological crisis, and health issues, necessitating sustainable, renewable, environmentally friendly, and economically feasible biofuels and antimicrobial compounds. In the current study R. communis L seeds were used as a feedstock for biorefinery, aiming to produce biodiesel using chemical transesterification and to evaluate its antimicrobial potential. The identification of bioactive molecules as prospective, affordable pharmaceutical resources derived from herbal plants is one novel approach to controlling the resistant diseases. R. communis L is widely used and well-known as a treatment for various diseases in traditional medicine. Phytochemical screening of R. communis L seed oil and extracts were carried out using qualitative phytochemical analyses. Its phytochemical properties are due to a variety of beneficial substances, including flavonoids, saponins, steroids/terpenes, resins/balsams, alkaloids, glycosides, tannins, and phenols, which are all detected in it. FTIR analysis also confirmed different functional groups in oil and extracts. In the current study, the antimicrobial potential of R. communis L extracts and seed oil, against five gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella pneumoniae, and Salmonella enterica), three gram-positive strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis) and three MDR strains (Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella) and five fungal clinical strains (Candida albicans, Aspergillus flavus, Aspergillus niger, Fusarium oxysporum and Curvularia lunata) and three phytopathogenic strains (Aspergillus flavus, Fusarium and Penicillium chrysogenum) were evaluated by agar well diffusion method. Ethyl acetate, and methanolic extracts of R. communis L showed high activity against all selected bacterial strains while against fungal strains these extracts showed high to low range of activities. Methyl acetate extract showed high to low range of values for bacterial strains while for fungal strains it showed high to moderate range. Oil only showed activities against E. coli and Fusarium and didn’t show any activity against all other bacterial and fungal strains. Ethyl acetate, methyl acetate, methanolic, n-Hexane and chloroform showed a good range of MICs values. Maximum antioxidant percentage was showed by 500mg/ml concentration of all extracts and oil. Extracts and oil didn’t show cytotoxicity on brine shrimps except chloroform which showed slight toxic effect. Extracted oil was utilized for biodiesel production through chemical transesterification. Five factors (Oil to methanol ratio, X Temperature, Agitation, Reaction time and Catalyst concentration) were statistically optimized through Plackett Burman design. The maximum volumetric yield of biodiesel was recorded 96%, with conditions: temperature 60oC, oil to methanol ratio 1:15, catalyst concentration 0.50%, 900rpm, and reaction time 60 minutes. Fourier transform infrared (FTIR) spectroscopy confirmed the production of biodiesel. The current study demonstrates that the R. communis L plant is an excellent feedstock for biorefineries.