Study of starch fermentation at low pH by Lactobacillus fermentum ogi E1 reveals uncoupling between growth and [alpha]-amylase production at pH 4.0

Calderon Santoyo M., Loiseau Gérard, Rodriguez Sanoja R., Guyot Jean-Pierre. 2003. Study of starch fermentation at low pH by Lactobacillus fermentum ogi E1 reveals uncoupling between growth and [alpha]-amylase production at pH 4.0. International Journal of Food Microbiology, 80 : 77-87.

Résumé : Lactobacillus fermentum Ogi E1 is an amylolytic heterofermentative lactic acid bacterium previously isolated from ogi, a Benin maize sourdough. In the present study, the effect of different pH between 3.5 and 6.0 on starch fermentation products and [alpha]-amylase production was investigated. Whereas a pH of 5.0 was optimum for specific growth rate and lactic acid production, growth was only slightly affected at suboptimal pH of 4.0 and 6.0. Over a pH range of 6.0 to 3.5, yields of product formation from substrate and of biomass relative to ATP were constant. These results showed that L. fermentum Ogi E1 was particularly acid tolerant, and well adapted to the acid conditions that develop during natural fermentation of cereal doughs. This acid tolerance may partly explain the dominance of L. fermentum in various traditional African sourdoughs. Surprisingly, [alpha]-amylase production, unlike growth, dropped dramatically when the strain was cultivated at pH 4.0 with starch. With maltose as substrate, the yield of [alpha]-amylase relative to biomass remained unchanged at pH 4.0 and 5.0, unlike that observed with starch. Based on the distribution of enzyme activity between extra- and intracellular fractions and fermentation kinetics, it appears that starch was first hydrolyzed into dextrins by [alpha]-amylase activity, and maltose was produced from dextrins by extracellular enzyme activity, transferred into the cell and then hydrolyzed into glucose by intracellular [alpha]-glucosidase.

Mots-clés Agrovoc : Lactobacillus fermentum, amidon de maïs, alpha amylase, fermentation, maltose, aliment fermenté, acidité

Mots-clés complémentaires : Ogi, Cinétique

Classification Agris : Q02 - Traitement et conservation des produits alimentaires
Q04 - Composition des produits alimentaires

Auteurs et affiliations

• Calderon Santoyo M., IRD (FRA)
• Loiseau Gérard, CIRAD-AMIS-AGROALIMENTAIRE (FRA)
• Rodriguez Sanoja R., UNAM (MEX)
• Guyot Jean-Pierre, IRD (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/518562/)

Métriques

[ Page générée et mise en cache le 2024-12-18 ]