Optimization Of Brown Rice Flour (Oryza Sativa L.) As An Alternative Medium For The Growth Of Staphylococcus Aureus Bacteria

Abstract

Background: The high dependence of microbiology laboratories on commercial media like Nutrient Agar (NA), which uses imported components (peptone and meat extract), highlights the need to explore local, cost-effective substrates. Red rice (Oryza sativa L.) is rich in complex carbohydrates, proteins, B-complex vitamins, and micronutrients that could potentially support microbial nutritional needs. Research Methods: An in vitro experimental approach with a post-treatment control scheme was employed in this study. The growth media derived from red rice flour was formulated across four gradient levels: 2.5%, 5.0%, 7.5%, and 10.0% (w/v), supplemented with 1.5% agar matrix, then compared with a positive control NA. S. aureus cultures were inoculated and incubated at 37°C for 24–48 hours. Growth parameters were evaluated descriptively based on colony density and thickness. Research Results: S. aureus can grow under all treatment variations. A 2.5% concentration results in limited growth, 5% and 7.5% concentrations show moderate growth, while a 10% concentration shows very dense and abundant colonies, comparable on a macroscopic level to standard NA media (fertility score 3). Conclusion: Red rice flour has proven to be potentially used as a base material for bacterial inoculum, with a 10% concentration being the most optimal for producing S. aureus growth equivalent to standard media.