Adnan Alkazah^(1)*, Abdulwahab Meri⁽¹⁾ and Bassam Aloklah⁽²⁾

(1) Food Science Department, Faculty of Agriculture, Damascus University, Damascus-Syria

(2) National Commission for Biotechnology, Damascus, Syria.

(* Corresponding author: Eng. Adnan alkazah E-mail: adnankaza@hotmail.com).

Received: 11/9/2021                                     Accepted:30/11/2021

Abstract

This research was conducted at the Faculty of Agriculture, Department of Food Science laboratories and National Commission for Biotechnology، Department of food and industrial biotechnology, Damascus, Syria. during 2020 and 2021 seasons. The current research aimed in optimization of the nutrients addition (yeast extract, dipotassium phosphate, manganese sulfate, magnesium sulfate) to the fermentation medium (cheese whey) for lactic acid production by Lactobacillus paracasei locally isolated from yoghurt, where this study based on the results of optimization conditions from former study, as following: fermentation temperature 37°C, pH 5.5, fermentation period 50 h. and shaking speed 150 round per minute, where the results thereby the production of 32.59 g/L of lactic acid. In the current study we based on advanced experiment design Response Surface Methodology using Minitap Optimization Method software to study each of the four factors separately and the effects of interactive factors between each other. The results revealed that the four interactive factors significantly affected in lactic acid production, and the relationship between these factors and lactic acid production take the shape of parabola, while the interaction relationship between all factors were not significant, and the coefficient of discrimination (R²) was = 0.86 (p>0.05). The results of nutrient optimization were as following: yeast extract 10 g/L, dipotassium phosphate 0.5 g/L, magnesium sulfate 0.2 g/L, manganese sulfate 0.04 g/L, and the results revealed production of 37.6 g/L of lactic acid. It can be noticed that the optimization of nutrient addition led to increase the lactic acid production by 5.01 g/L or 15.37%.

Keywords: Lactic acid, cheese whey, Lactobacillus paracasei, yeast extract

Full paper in Arabic: pdf