Characterization of biotechnological processes and products using high‐performance liquid chromatography (HPLC) VI. Determination of lactic acid and short‐chain carboxylic acids C₁–C₅

Abstract

Lactic acid and short-chain carboxylic acids C,-C, were analyzed on a n Aminex HPX-87H column using UV and RI detection. The HPLC method was applied to complex fermentation media of a microbial lactic acid formation process. The resulting chromatograms of the yeast extract or culture medium showed some W-absorbing substances that interfered partially with peaks of shortchain carboxylic acids. I n contrast t o UV monitoring, R I detection gave only a few small peaks of these so-called "background chromatograms". Also glucose used as substrate could be quantified in the culture medium, because of which R I detection should be preferred. Furthermore, a self-prepared cation-exchange resin (SAC = S-DVB) based on a poly(styrenedivinylbenzene) partially comparable in its properties with Aminex resins was useful for fast (about 4 minutes) and not too expensive determinations of lactic and acetic acid in fermentation media. Applying this separation system to fermentation solutions detected b y R I as well as UV monitoring results in the quantitative analysis of lactic acid kinetics identical with a n Aminex HPX-87H column were achieved. Finally, the simplicity of lactic-acid analysis is illustrated by examples of dairy products only centrifugated and diluted in double distilled water before injecting on a cation-exchange column.

Lactic acid production from submerged fermentation of broken rice using undefined mixed culture

“…The quantification of LA in supernatants derived from kinetic studies of best experimental conditions defined through the values of total acidity, both Lactobacillus amylovorus and mixed culture was done by high-performance liquid chromatography (Gey et al 1990). Briefly, the separation was done in Aminex HPX-87H column (300 × 7.8 mm, BioRad, Richmond, CA, EUA) using refractive index detector.…”

Development of optimal medium for production of commercially important monoclonal antibody 520C9 by hybridoma cell

“…Lactic acid was measured by HPLC (Agilent, Santa Clara, CA, USA) using HP-Aminex-87H column (Biorad, Hercules, CA, USA) with column temperature at 60°C and mobile phase of 5 mM sulfuric acid with flow rate of 0.6 ml/min. (Gey et al 1990). Ammonia was measured by Nessler's reagent (Morrison 1971).…”

Nitrosation and analysis of amino acid derivatives by isocratic HPLC

“…On the same column, disaccharides, hexoses, pentoses, organic acids, ketones, alcohols, polyols and more different molecules can be separated and simultaneously quantied in the same sample. The method is well established in microbial biotechnology 8 and has been used to quantify substrate uptake and metabolite synthesis in cultures of bacteria, 9,10 lamentous fungi, 11,12 and microalgae. 13,14 The method has also been used to analyse metabolites in e.g.…”