チーズホエー透過液を付加価値成分として利用した乳酸ブロピオン酸カルシウムの酵素合成

Lactobionic acid (LBA) and its salt form (e.g., lactobionate [LBN]) have emerged as high-value-added functional ingredients in food and pharmaceutical applications, such as acidulant, antioxidant, metal chelator, and carrier in drug delivery systems. Enzymatic oxidation has been employed as a nontoxic, cost-effective, and environmentally friendly approach for the synthesis of LBA/LBN. The current study investigated, first, the feasibility of producing calcium lactobionate (Ca-LBN) via enzymatic oxidation using cheese whey permeate as a substrate at high concentration, and second, the bioactivity of the resulting Ca-LBN. The production experiment was performed using reconstituted cheese whey permeate solution (300 g·L^-1 lactose) as a substrate, Ca(OH)₂ as a titrant base, oxidase (dosage: 400 U·kg^-1 lactose), and catalase (dosage: 168,000 U·kg^-1 lactose) in a laboratory bioreactor. Target critical control parameters, such as pH 6.40; dissolved oxygen: 44%; and temperature: 38°C, were defined and monitored using an industrial human-machine interface (HMI) to ensure operational stability. The consumption of Ca(OH)₂ was used to calculate real-time molar conversion rate (MCR_RT) and accumulative molar conversion yield (MCY) according to the pH-stat method. Enzymatic oxidation reaction continued for 7 h, and MCY was observed at nearly 99%. The MCR_RT rapidly reached a plateau value of ∼470 mmol·h^-1 within 20 min of the process. The critical operational parameters remained controlled by the HMI cascade, suggesting that the process is scalable. The DPPH-radical scavenging and ferrous ion chelating activity of the obtained LBN could not be confirmed based on the colorimetric assays used in the present work; however, characterization processes need to be further optimized. The obtained knowledge may be applied to the scalable production of LBA/LBN, enabling higher yields and an efficient manufacturing process.