EXPLORING PROTEIN-RICH PLANT SUBSTRATES FOR SINGLE-CELL PROTEIN PRODUCTION

Abstract

Background: Protein deficiency remains a global nutritional challenge, particularly in developing countries where malnutrition and food insecurity are prevalent. According to UNICEF, one in five children in Pakistan suffers from acute malnutrition, manifesting as stunted growth, muscular weakness, skin lesions, and hormonal imbalances. With increasing economic instability and reduced accessibility to conventional protein sources, alternative nutrient-rich and low-cost substrates such as Moringa oleifera, curry leaves, and pea plant waste are being explored for single-cell protein (SCP) production. SCP, derived from microbial biomass, provides a sustainable protein source capable of addressing dietary deficiencies and supporting public health.

Objective: The study aimed to evaluate the potential of Moringa oleifera, curry leaves, and pea plant waste as plant-derived substrates for the production of single-cell protein using Saccharomyces cerevisiae as a microbial model.

Methods: Vegetable waste from pea plants and leaf samples of Moringa oleifera and curry leaves were collected, shade-dried, powdered, and hydrolyzed using 10% hydrochloric acid. The filtrates were utilized as substrates for yeast fermentation under controlled conditions (pH 5.5; 25–28°C for 8 days). The S. cerevisiae culture was centrifuged at 4,000 rpm for 15 minutes at 4°C before protein estimation. Protein concentration was determined using the Bradford assay with Bovine Serum Albumin (2.0 mg/mL) as the standard, and absorbance was measured at 595 nm.

Results: Dried plant substrates showed higher protein concentrations than fresh ones. Moringa oleifera exhibited the highest protein yield of approximately 28%, followed by pea plant waste at 25%, while curry leaves recorded 18%. Increasing substrate hydrolysate concentration from 2% to 4% enhanced protein production by 35%. Pea waste and Moringa oleifera demonstrated well-defined exponential growth phases, while curry leaves showed prolonged lag phases due to inhibitory phytochemicals.

Conclusion: The findings suggest that Moringa oleifera and pea plant waste are effective, sustainable, and low-cost substrates for SCP production, offering potential solutions to protein deficiency and waste management challenges. The study emphasizes the value of optimizing plant-derived substrates to improve microbial protein yield for human and animal nutrition.