Formulation and evaluation of alternative microbial culture media to agar-based media using local plants seeds

Abstract

Access to current microbiological culture media is characterized by some limitations including high cost, amongst others. This affects holistic learning,  hence the need for formulation of alternative microbial culture media using local plants that are affordable, readily available, and accessible. This work  sought to formulate and evaluate local plants seeds of Brachystegia eurycoma Harms, Mucuna sloanei Fawc and Rendle and Detarium microcapum Guill  and Perr as alternative microbial culture media to agar-based microbial culture media. The seeds were processed and extracted using cold maceration  method. Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger were collected and sub-cultured to obtain pure isolates.  Antimicrobial susceptibility test of the different pulverized plants seeds extracts was carried out using agarwell diffusion technique. Residual  antimicrobial activities were inactivated using standard physicochemical and microbiological procedures. Microbial media were formulated from the  antimicrobial-free pulverized seeds of methanol extract as gelling agents or agar replacement using pour plating method while microbial inoculation and  colony count was carried using standard methods. Assessed textural and microbiological properties, gelling range (0.056 -0.07 g/mL) and time (3-40  min) of the inactivated pulverized seeds showed significant (p<0.05) varying properties compared to Nutrient agar (NA) and Sabouraud dextrose agar  (SDA) as controls (0.028-0.056 g/mL and 18-30 minutes). The formulated culture media showed significant microbial growth in sabouraud dextrose broth  than nutrient broth compared to control. Colony counts for S. aureus (1+0.34) for Mucuna. sloanei and Candida albicans (5+0.58) for Brachystegia  eurycoma was less significant by a factor of 10 and 8 at p<0.05, within 24 and 72 hours compared to NA (15+1.58) and SDA (43+0.00). There was  significant (p<0.05) colony count within 48 and 120 hours which was too numerous to count (TNTC) for bacteria and fungi compared to NA and SDA  (TNTC). Therefore, the formulated media showed significant (p<0.05) comparative properties to agar-based microbial media with significant microbial  growth and colony count. There is a feasibility of developing alternative media from either of the 3 plants to aid effective microbiological work in schools  and laboratories.