Use of Cowpea and Pigeon pea as Nutritional Ingredients in Culture Media
Background: Dehydrated commercial culture media are hygroscopic and expensive. Cheap, locally available plant seeds such as cowpea (Vigna unguiculata) and pigeon pea (Cajanus cajan) could be used in the design and formulation of microbial culture media in order to reduce the cost.
Objective: To make use of locally cheap seeds as a basic nutrient medium for the isolation of different microorganisms.
Materials and methods: Solid culture media from locally available plants were designed to include three types, (i) simple; (ii) enriched with the addition of human blood; (iii) differential with lactose and phenol red as a pH indicator, and formulated to contain cowpea and pigeon pea flours in combination in a concentrations of 2%. The name DANIEL & SHAMSOUN (D & S) was used for the designed media. Twenty bacterial species and Candida albicans were inoculated for the observation of the growth response.
Results: On D & S simple medium all the organisms grew typically except, Corynebacterium diphtheriae which did not grow and Streptococcus pyogenes and Neisseria meningitidis which revealed atypical colonies. On D & S human blood agar medium, all the organisms grew typically, but the β- hemolysis of some of the β-haemolytic species was not detected and some species revealed green pigmented colonies and green pigmentation on the medium. On D & S differential medium, all lactose-fermenting species revealed typical, yellow colonies and all non-lactose-fermenting species revealed typical, pink-red colonies, except, Vibrio cholerae, Bacillus cereus and Candida albicans which revealed typical, yellow colonies.
Conclusion: The flours of cowpea and pigeon pea are good sources of protein, carbohydrates and minerals, so they can be used in the preparation of different types of culture media for the isolation of different species of bacteria and Candida albicans as shown in this study.
Key words: Cowpea, pigeon pea, nutrient medium, DANIEL & SHAMSOUN.