Purification and characterization of extracellular proteinases excreted by a strain of Bacillus subtilis BS₂, isolated from fermented African locust bean ‘iru’

Abstract

Proteinases were excreted by strains of Bacillus subtilis during fermentation of African locust bean cotyledons. Those excreted by one strain were purified and characterized by ammonium sulphate precipitation, ion‐exchange chromatography (IEC), gel filtration, inhibition tests and polyacrylamide gel electrophoresis (PAGE). Three proteinases and an esterase without proteolytic activity were identified. A serine proteinase which showed a high degree of hydrophobicity and a neutral proteinase were present. The third proteinase showed both proteolytic and esterolytic activities, and had multiple electrophoretic mobilities on polyacrylamide gel.

Incubation and Fermentation of African Locust Beans (Parkia Biglobosa) in Production of "Dawadawa"

“…This lypolytic activity is attributable to enzymes produced in the dawadawa by microbial activity – usually of the Baccilus spp. (Odunfa 1981; Aderibigbe and Odunfa 1988). Where fermentation is poor, this characteristic aroma will be lacking as observed in the samples from jute and polythene bags.…”

“…Odunfa (1981) also recorded pH increase of up to 8.1 during the first 30 h of fermentation. This increase in pH could be due to the production of ammonia as a result of the activity of proteolytic enzymes produced by B. subtilis (the main fermenting organism), which makes the condition of the dawadawa alkaline (Sundhagul 1972;Antai and Ibrahim 1986;Aderibigbe and Odunfa 1988;Sarkar et al 1994;Steinkraus 1996). Ammonia production has been reported as a common feature associated with fermentation of vegetable proteins, e.g., in the fermentation of soya beans to produce "tempe" (Owens et al 1997).…”

“…In Japan, the fermentation is usually inoculated with selected pure cultures of Bacillus subtilis (Ohta 1986), but in other countries, the fermentations use traditional methods and rely on natural contamination. In all cases, however, the major bacteria involved are strains of B. subtilis (Sundhagul 1972; Antai and Ibrahim 1986; Ohta 1986; Odunfa 1986; Aderibigbe and Odunfa 1988; Sarkar et al. 1994).…”

“…In Japan, the fermentation is usually inoculated with selected pure cultures of Bacillus subtilis (Ohta 1986), but in other countries, the fermentations use traditional methods and rely on natural contamination. In all cases, however, the major bacteria involved are strains of B. subtilis (Sundhagul 1972;Antai and Ibrahim 1986;Ohta 1986;Odunfa 1986;Aderibigbe and Odunfa 1988;Sarkar et al 1994). The bacteria are strongly proteolytic and thus quickly hydrolyze the proteins in the beans giving amino acids which are further metabolized, giving rise to changes in pH value from about 6.50 to 8.50 and the development of strong ammonical odor (Sarkar et al 1994).…”

PURIFICATION OF A PROTEASE FROM AN ALKALOPHlLIC BACILLUS SUBTILIS CHZ1 ISOLATED FROM A ZIMBABWEAN HOT SPRING

“…A number of proteases isolated from microorganisms exhibit more than one band on SDS-PAGE gels and this has been attributed to either multiple forms of the protease (Ederibigbe and Odunfa 1988;Green 1985) or to posttranslation modification. These changes may be deamination, phosphorylation and conformational changes of the polypeptide chain.…”