KINETIC STUDY OF THE UTILISATION OF DIFFERENT SUBSTRATES TO LACTIC ACID USING Lactobacillus delbrueckii

Abstract

Abstract

Lactic acid fermentation includes several reactions in association with the

microorganism growth.  A kinetic study was performed of the utilisation of multiple

substrates to lactic acid using lactobacillus delbrueckii. Batch fermentation was

performed to study effect of different substrates such as glucose, fructose and sucrose.

The objective of this research is to study kinetics grow microbial. A anaerobic

fermentation were studied in 3 litres stirred fermentor ( Biostat B Model) with working

volume of 1 liter, temperature : 40 ^oC, pH = 6.0, inoculums size : 5% , sugar

concentration =  20 g/1. During the first hours of fermentation, glucose and fructose

accumulated in the medium and the rate of  hydrolysis of sucrose to glucose and

fructose was faster than conversion of these substrate. The maximum concentration of

glucose and fructose was 5.82 and 5. 14 g/l respectively. The sucrose, glucose, and

fructose consumption completely utilized at 56, 68, and 104 hours, respectively.

Kinetic parameter for maximum .specific growth rate in glucose, fructose and sucrose

is 0.103, 0.0448, and 0.0398 (h^-1), respectively. The saturation constant is 2.13, 2.67,

and 3.32 g/1.

Key Words: Kinetic Study, Sugars, Lactic Acid, Maximum Specific Growth Rate and

Saturation Constant