Lactic acid is considered as a very important chemical compound with significant applications in pharmaceuticals, cosmetics and especially in the food industry. New applications, such as degradable plastics made from poly (lactic) acid, have the potential to greatly expand the market for lactic acid, if more economical processes could be developed. Industrial processes for the production of lactic acid typically use sucrose from cane and beet sugar, whey containing lactose and maltose and dextrose from hydrolyzed starch. The pulp of carob (Ceratonia siliqua L.) pods contains high contents of sugar (sucrose, fructose and glucose) and can be employed as a raw material for the production of lactic acid. The aim of the present study consists in the optimization of physicochemical parameters (temperature and pH) , and also the culture medium for producing lactic acid by Streptococcus thermophilus on the carob extract based medium. The optimum pH and temperature for bioactive metabolite production were 6.6 and 41°C respectively. Highest lactic acid production (29.95 g/L) was found when the strain was inoculated into the medium amended with Tween 80 at the concentration of 1%. Carob extract could serve as a good potential source of raw materials for the efficient production of lactic acid by Streptococcus thermophilus.
Bouhadi D, Raho B, Hariri A, Benattouche Z, Ould Yerou K, Sahnouni F