Abstract

Mohammed Yakubu74401*, Hauwa Hajjagana Laminu74399 and Mohammed Adamu Milala74400

A microbial protein termed as Single Cell Protein (SCP) is regarded as an alternative protein to complement the conventional proteins. As protein requirement is rising, high concentration of nucleic acid present in SCP serves as great limitation for its consumption as food. This study is aimed at producing SCP with reduced nucleic acids concentration from banana peels using Saccharomyces cerevisiae through submerged fermentation. The fermentation media was prepared as Non-supplemented Media (NM) (only processed peels hydrolysate with distilled water) and Supplemented Media (SM) (mineral salts with processed peels hydrolysate) after which, a high microbial growth and protein production (680 μg/μl) was observed on NM compared to 410 μg/μl that was obtained on SM after 120 hrs of fermentation. The products were further treated with 5%, 10% and 20% solution of each of Sodium Hydroxide (NaOH), Sodium Chloride (NaCl) and Glycine (Gly)-NaOH buffer at the pH of 10.3 to reduce the nucleic acids content. Treatment with NaCl showed high decrease in nucleic acid content (51.3 ng/μl-30.1 μg/μl) with corresponding greater decrease in protein content (410 μg/ μl-190 μg/μl) at 20% treatment. However, treatment with Gly-NaOH buffer has reduced the protein quantity from 680 to 330 μg/μl (SM) and 410 to 250 μg/ μl (SM) and decreased the nucleic acid content (47.9 to 23.3 μg/μl and 51.3 to 24.5 μg/μl on NM and SM respectively), while the protein and nucleic acid contents lost (680 to 110 μg/μl and 47.9 to 36.7 μg/μl) was observed on NaOH treatment. Amino Acids (AA) analysis indicated the presence of the 9 essential AA and 2 non-essential AA (cystine and tyrosine) in the product. The crystalized form of the product was also obtained through centrifugation at 4000 (revolutions per minute) rpm for 45 minutes. Therefore, NM banana peel hydrolysate proved to be good source of SCP with high protein content and more essential AA. The use of Gly-NaOH buffer in reducing the nucleic acid content of the SCP produced proved to be more effective, considering the less proteolytic effect they showed on the SCP produced.