دانلود ترجمه مقاله بررسی وپژگیها و تولید میکروبی اسید گلوکونیک

فهرست مطالب:

خلاصه
مقدمه
تاریخچه
رفتار فیزیوشیمیایی
اندازه گیری
کاربرد
تولید اسید گلوکونیک
مقدمه
تولید اسید گلوکونیک توسط قارچ فیلامنتوس
گلوکز اکسیداز
مواد خام ارزان تر به عنوان سوبسترا
استفاده از تخمیر حالت جامد SSF
تولید اسید گلوکونیک توسط باکتری
مخمر
غیر فعال سازی
ریکاوری
بیولوژی مولکولی
نتیجه گیری

بخشی از ترجمه:

اگرچه تولید اسید گلوکونیک یک فرایند اکسیداسیونی ساده است که با روش های الکتروشیمیایی، بیوشیمیایی و بیوالکتروشیمیایی انجام می شود، تولید توسط فرایند تخمیر در بر گیرنده قارچ ها و باکتری ها بوده و  عملکرد تجاری خوبی داشته است. در افزایش درک مکانیسم مولکولی فرایند تخمیر توسط میکروارگانیسم های متعدد و  فرایند تولید کارامد که به ۵ دهه پیش بر می گردد پیشرفت های عظیمی انجام شده است. با این حال توسعه فرایند های اقتصادی تر برای تبدیل گلوکز به اسید گلوکونیک با طول قفسه ای یا نگهداری بیشتر امیدوار کننده است. این ملزومات را می توان با سیستم انزیمی رفع کرد. دیگر روش بهبود استفاده از سوبستراهای ارزان، نظیر متانول  به جای گلوکز است.

بخشی از مقاله انگلیسی:

Introduction Gluconic acid (pentahydroxycaproic acid, Fig. 1) is produced from glucose through a simple dehydrogenation reaction catalysed by glucose oxidase. Oxidation of the aldehyde group on the C-1 of b-D-glucose to a carboxyl group results in the production of glucono-d-lactone (C6H10O6, Fig.1) and hydrogen peroxide. Glucono- -d-lactone is further hydrolysed to gluconic acid either spontaneously or by lactone hydrolysing enzyme, while hydrogen peroxide is decomposed to water and oxygen by peroxidase. The gluconate pathway is detailed in Fig. 2. The conversion process could be purely chemical too, but the most commonly involved method is the fermentation process. The enzymatic process could also be conducted, where the conversion takes place in the absence of cells with glucose oxidase and catalase derived from A. niger. Nearly 100 % of the glucose is converted to gluconic acid under the appropriate conditions. This method is an FDA approved process. Production of gluconic acid using the enzyme has the potential advantage that no product purification steps are required (1) if the enzyme is immobilised, e.g. the use of a polymer membrane adjacent to anion-exchange membrane of low- -density polyethylene grafted with 4-vinylpyridine (1). However, this approach is not yet common in the industry, and it will not be considered in the review. History Gluconic acid production dates back to 1870 when Hlasiwetz and Habermann discovered gluconic acid (2). In 1880 Boutroux (3) found for the first time that acetic acid bacteria are capable of producing sugar acid. In 1922 Molliard (4) detected gluconic acid in the Sterigmatocystis nigra, now known as Aspergillus niger. Later, production of gluconic acid was demonstrated in bacterial species such as Pseudomonas, Gluconobacter, Acetobacter, and various fungal species. Studies of Bernhauer (5– ۷) showed that A. niger produced high yields of gluconic acid when it was neutralised by calcium carbonate and the production was found to be highly pH dependent. However, it was found that with Penicillium sp., the pH dependence is not as critical when compared to A. niger, indicating that there was some correlation between the amount and time-dependent appearance of organic acids, such as gluconic acid, citric acid, oxalic acid, which are formed under different conditions. Gluconic acid production has been extensively studied by May et al. (8), Moyer (9), Wells et al. (10), and Stubbs et al. (11) using A. niger. Using Penicillium luteum and A. niger Currie et al. (12) filed a patent employing submerged culture, giving yields of gluconic acid up to 90 % in 48–۶۰ h. Later Moyer et al. (13) used A. niger in pilot plant studies and produced as high as 95 % of theoretical yields in glucose solution of 150 to 200 g/L in 24 h. Porges et al. (14) found that the process could be run semicontinuously, by the reuse of the mycelium for nine times repeatedly where the inoculum was recovered either by filtration or centrifugation. Findings of Moyer et al. (13) showed that efficiency of more than 95 % could be achieved by the addition of glucose at 250 g/L and boron compounds (1 % in solution of 250 g/L glucose) at later stages of the fungal growth with the reuse of mycelium in cycles of 24 h each. Current commercial production of sodium gluconate uses submerged fermentation with A. niger and is based on the modified process developed by Blom et al. (15). It involves fed-batch cultivation with intermittent glucose feedings and the use of sodium hydroxide as neutralising agent. pH is held at 6.0–۶٫۵ and the temperature at about 34 °C. The productivity of this process is very high, since glucose is converted at a rate of 15 g/ (L·h.) Properties Physicochemical behaviour Gluconic acid is a noncorrosive, nonvolatile, nontoxic, mild organic acid. It imparts a refreshing sour taste in many food items such as wine, fruit juices, etc. Sodium gluconate has a high sequestering power. It is a good chelator at alkaline pH; its action is comparatively 186 S. RAMACHANDRAN et al.: Gluconic Acid: A Review, Food Technol. Biotechnol. 44 (2) 185–۱۹۵ (۲۰۰۶) Fig. 2. General gluconate pathways better than EDTA, NTA and other chelators. Aqueous solutions of sodium gluconate are resistant to oxidation and reduction at high temperatures. It is an efficient plasticizer and a highly efficient set retarder. It is easily biodegradable (98 % at 48 h). It has an interesting property of inhibiting bitterness in foodstuffs. Concentrated gluconic acid solution contains certain lactone structures (neutral cyclic ester) showing antiseptic property.