Use Of Prosopis Africana Seed Hydrolysate As Peptone Source For Microbial Growth Media

ABSTRACT

There is a growing industrial demand for peptones of non-animal origin owing to legislations as

well as outbreak of animal-associated diseases. Microbiological growth media developed from

legumes as sources of protein hydrolysates are limited. It is, therefore, the aim of this study, to

produce comparatively standard protein hydrolysates from Prosopis africanaseed that can be

used as peptone for microbial culture in place of animal peptone.

Prosopis africana seeds (2.5kg) were purchased from a local market in Mbu-Akpoti, Enugu

State of Nigeria. Stones and bad seeds were sorted out. The selected seeds were washed using

distilled water and then boiled until the seed coats became soft. The softened seed coats were

manually peeled off to reveal the cotyledons, which were collected, washed, dried and powdered.

The powdered cotyledon was subjected to hydrolysis using the enzyme papain or hydrochloric

acid. Metal ions, vitamins as well as proximate compositions of the hydrolysates were

determined using standard methods. Amino acid analysis was done using HPLC. Growth

patterns of Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli,

Candida albicans and Aspergillus niger were monitored in the media formulated using the seed

hydrolysates. Peptone in commercially available MacConkey, Mannitol-salt and Sabouraud

dextrose media was substituted with the seed hydrolysates and these were used as selective or

differential media for specific organisms.

In assessing the above parameters, comparism between commercially available peptone and the

hydrolysates from Prosopis africana seed were made.

The results of the analyses revealed that papain hydrolysed Prosopis africana seed (PHPs)

ranked highest in terms of microbial growth support when compared to AHPs. PHPs and AHPs

had moisture contents of 32.7and 83.3% respectively as against 3.93% in CP. The ash values

were 3.05 and 0.15% for PHPs and AHPs respectively whereas CP had 4.08%. Crude proteins of

39.69 and 12.78% were also observed in PHPs and AHPs respectively. The hydrolysates were

found to be rich in vitamins A, B, C and E and also in metal ions. Serine, threonine and lysine

were the most dominant amino acids in the seed hydrolysates. Escherichia coli, Staphylococcus

aureusand Candida albicans all thrived well in their respective selective media made with the

hydrolysates, and this compared favourably well with commercially available peptone.

Production and use of Prosopis africana seed hydrolysate as source of peptone will help to bring

down the cost of peptones which are currently being imported and sold at very high rates in

Nigeria.