Bio-Based Production of Dimethyl Itaconate From Rice Wine Waste-Derived Itaconic Acid.

Dimethyl itaconate is an important raw material for copolymerization, but it is not synthesized from itaconic acid by organisms. Moreover, Corynebacterium glutamicum is used as an important industrial host for the production of organic acids, but it does not metabolize itaconic acid. Therefore, the biosynthetic route toward dimethyl itaconate from itaconic acid is highly needed. In this study, a biological procedure for dimethyl itaconate production is developed from rice wine waste-derived itaconic acid using the engineered C. glutamicum strain. The first step is to investigate the effect of the co-overexpression of the codon-optimized cis-aconitic acid decarboxylase (CadA*) and a transcriptional regulator of genes involved in acetic acid metabolism (RamA) on itaconic acid production. The second step is to convert itaconic acid into dimethyl itaconate by lipase-catalyzed esterification. The CadA* and RamA-overexpressing CG4 strain increases the itaconic acid concentration under N-starvation with glucose and acetic acid compared with the concentration produced in the base mCGXII medium with glucose. Furthermore, the rice wine waste-derived itaconic acid is successfully converted into dimethyl itaconate using lipase from Rhizomucor miehei and a methanol substrate. This study is the first trial for bio-based production of dimethyl itaconate from rice wine waste-derived itaconic acid.

The Availability of Skin Perfussion Pressure Measurement in the Prediction of Ischemic Limb Ulcer Healing

PURPOSE: Critical limb ischemia (CLI) is equated with a need for limb salvage. We studied whether measurement of skin perfusion pressure (SPP) can be used to accurately identify the ampuation level of those patients with CLI who require major amputation and predict the patients whose foot ischemic ulcer would heal or not after vasodilator treatment for over 4 weeks. METHODS: Fifty-one patients with a nonhealing foot ulcer were studied prospectively at Yeungnam university hospital. Age range was 46 to 78 years old with average 68 years old and male to female ratio was 3.3:1. Patients were included in the study if informed consent for medication of vasodilators was obtained, and patients were excluded if there was uncontrolled sepsis or if they required imminent amputation. We used PGE1 (Opalmon(R), 6 tablets/day #3 for 6 weeks, 100 mg/tablet) in 20 cases, PGI2 (Beraprost(R), 6 tablets/day, #3 for 6 weeks, 20 mg/tablet) in 16 cases and Argatroban (antithrombin: Novastan(R) 2 amples/day #2 IV for 4 weeks, 10 mg/ample) in 15 cases. The ankle pressure was checked for each limb. Measurements of SPP were made with photoplethysmography (Life Sciences MVL Modulab(R)) at the metatarsal level which were mostly located at the proximal site of ulcer in viable tissue. The SPP measuements were compaired with the clnical results of therapy (group I: stop medication and major amputation in 7 cases, group II: failed to heal in 18 cases, group III: ulcer healed in 26 cases) in group II & III. We calculated overall acuracy of SPP measurement for prediction of limb ischemic ulcer healing. RESULTS: The ankle pressure or Ankle Brachial Index (ABI) was not predictive of the need for the outcome of drugs therapy. Average SPPs were 12+/-6 mmHg in group I,27+/8 mmHg in group II and 45+/-7 mmHg in group III. The overall predictive accuracy of SPP over 40 mmHg for ulcer healing was 80%. CONCLUSIONS: SPP measurement with PPG is an objective, easy and effective noninvasive method that can be used to predict ischemic ulcer healing.