M C Palacios1, M Haros, C M Rosell, Y Sanz. 1. Cereal Laboratory, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Valencia, Spain.
Abstract
AIMS: To screen for phosphatase and phytase activities in Lactobacillus isolated from diverse ecosystems and to determine the biochemical properties and the factors that regulate the synthesis of the enzyme responsible for these activities in the selected strain, Lactobacillus pentosus CECT 4023. METHODS AND RESULTS: These activities were determined spectrophotometrically by using p-nitrophenyl phosphate and sodium phytate as substrates. They were maximal at the onset of the stationary phase of growth and repressed in the presence of high glucose concentration and inorganic phosphate. The enzyme responsible for these activities was an acid phosphatase (E.C.3.1.3.2.), with a molecular mass of 69 kDa. The activity was optimum at pH 5.0 and 50 degrees C. It hydrolysed mono-phosphorylated substrates and phytate, albeit at lower rates. It was inhibited by iodoacetic acid, phenyl-methylsulphonyl fluoride, di-sodium pyrophosphate and Ca+2 while activated by Co+2 and low concentrations of L-ascorbic acid and EDTA. CONCLUSIONS: Lactobacillus pentosus CECT 4023 produces a nonspecific acid phosphatase that hydrolyses a number of mono-phosphorylated substrates and phytate. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that the phosphatase from L. pentosus CECT 4023 could partly contribute to reduce the phosphorylation degree of phytate and its derivatives and, thereby, their anti-nutrient properties during fermentation processes.
AIMS: To screen for phosphatase and phytase activities in Lactobacillus isolated from diverse ecosystems and to determine the biochemical properties and the factors that regulate the synthesis of the enzyme responsible for these activities in the selected strain, Lactobacillus pentosus CECT 4023. METHODS AND RESULTS: These activities were determined spectrophotometrically by using p-nitrophenyl phosphate and sodium phytate as substrates. They were maximal at the onset of the stationary phase of growth and repressed in the presence of high glucose concentration and inorganic phosphate. The enzyme responsible for these activities was an acid phosphatase (E.C.3.1.3.2.), with a molecular mass of 69 kDa. The activity was optimum at pH 5.0 and 50 degrees C. It hydrolysed mono-phosphorylated substrates and phytate, albeit at lower rates. It was inhibited by iodoacetic acid, phenyl-methylsulphonyl fluoride, di-sodium pyrophosphate and Ca+2 while activated by Co+2 and low concentrations of L-ascorbic acid and EDTA. CONCLUSIONS:Lactobacillus pentosus CECT 4023 produces a nonspecific acid phosphatase that hydrolyses a number of mono-phosphorylated substrates and phytate. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that the phosphatase from L. pentosus CECT 4023 could partly contribute to reduce the phosphorylation degree of phytate and its derivatives and, thereby, their anti-nutrient properties during fermentation processes.