Growth and α-amylase production by strains of Lactobacillus plantarum and Rhizopus oryzae cultures in cassava starch medium

Abstract

A cassava starch medium was used to analyse the dynamics of batch growth and α-amylase production of strains of Lactobacillus plantarum and Rhizopus oryzae isolated from cassava dried chips. The strains displayed a growth of 0.5h^-1 and 0.55 h^-1, a biomass yield on cassava starch of 0.49g/g and 0.5g/g, a maximum specific cassava starch uptake rate (μm/Yx/s) of 2.98 mmol g^-1 h^-1 and 3.21 mmol g^-1 h^-1, a maximum oxygen uptake rate of 14.7 mmol g,sup>-1h^-1 and 12.94 mmol g^-1h^-1, an oxygen efficiency of growth of 0.565 and 0.58, a carbon recovery of 1.035 and 0.97, and an energy recovery of 1.0 and 0.95 respectively. Enough α-amylase enzymes were synthesized, and cassava starch hydrolysis was not a limiting factor for growth of both strains. Theses results suggest the possibility to use these strains for developing a dual starter culture for cassava fermentation, and α-amylase production from cassava starch medium.

Keywords: cassava, α-amylase, Lactobacillus plantarum, Rhizopus oryzae, starter culture

Cameroon Journal of Experimental Biology Vol. 1(2) 2005: 107-115