Open AccessOptimization of the Process for the Production of L (+)‐Lactic Acid from Cull Potato by Rhizopus oryzae
Author(s) -
Liu Y.,
Wen Z.,
Liao W.,
Liu C.,
Chen S.
Publication year - 2005
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.200520079
Subject(s) - rhizopus oryzae , fermentation , lactic acid , food science , substrate (aquarium) , lactic acid fermentation , raw material , yield (engineering) , response surface methodology , strain (injury) , central composite design , biomass (ecology) , chemistry , biology , bacteria , agronomy , materials science , chromatography , composite material , ecology , organic chemistry , genetics , anatomy
Cull potato is currently an under‐utilized biomass in the potato processing states of the USA. L (+)‐Lactic acid production by three Rhizopus strains and one homofermentative, facultative anaerobic Lactobacillus amylophilus strain was investigated using potatoes as the sole nutrient supply in the culture medium. Rhizopus oryzae NRRL 395 was chosen as the strain for further studies because it showed the highest lactate yield. The fermentation conditions for seed cultures were studied for three treatment structures using a completely randomized design. Optimum conditions for the seed culture were determined to be 2 % potato medium, 10 4 spores/mL concentration, and 24 h of fermentation. Plackett‐Burman and central composite designs were used to screen and optimize the factors for lactic acid production. Substrate (potato) concentration, fermentation temperature, and shaking speed were found to be the most significant factors affecting both the yield and concentration of lactate. Optimum values for substrate concentration, fermentation temperature, and shaking speed were 10 %, 27 °C, and 170 rpm, respectively. Under these optimum conditions, the lactate concentration was predicted by the model to be 35.5 g/L, which was verified by the experimental data (33.3 g/L). The results indicate that cull potato can be an effective feedstock for R. ryzae NRRL 395 in the production of lactic acid.