Sharafi Sm, Rasooli I, Beheshti-Maal K
M.Sc (Microbiology student), Department of Biology, Shahed University, Tehran-Qom Express Way, Opposite Imam Khomeini's shrine, Tehran-3319118651, Iran.
Iran J Microbiol. 2010 Mar;2(1):38-45.
Acetic acid bacteria (AAB) are useful in industrial production of vinegar. The present study aims at isolation and identification of acetic acid bacteria with characterization, optimization, and evaluation of their acetic acid productivity.
Samples from various fruits were screened for presence of acetic acid bacteria on glucose, yeast extract, calcium carbonate (GYC) medium. Carr medium supplemented with bromocresol green was used for distinguishing Acetobacter from Gluconobacter. The isolates were cultured in basal medium to find the highest acetic acid producer. Biochemical tests followed by 16S rRNA and restriction analyses were employed for identification of the isolate and phylogenic tree was constructed. Bacterial growth and acid production conditions were optimized based on optimal inoculum size, pH, temperature, agitation, aeration and medium composition.
Thirty-seven acetic acid bacteria from acetobacter and gluconobacter members were isolated. Acetic acid productivity yielded 4 isolates that produced higher amounts of acid. The highest producer of acid (10.03%) was selected for identification. The sequencing and restriction analyses of 16S rRNA revealed a divergent strain of Acetobacter pasteurianus (Gene bank accession number#GU059865). The optimum condition for acid production was a medium composed of 2% glucose, 2% yeast extract, 3% ethanol and 3% acid acetic at inoculum size of 4% at 3L/Min aeration level in the production medium. The isolate was best preserved in GYC medium at 12°C for more than a month. Longer preservation was possible at -70°C.
The results are suggestive of isolation of an indigenous acetic acid bacteria. Pilot plan is suggested to study applicability of the isolated strain in acetic acid production.
醋酸菌在食醋工业生产中具有重要作用。本研究旨在分离鉴定醋酸菌，并对其特性、产酸能力进行优化和评估。
以葡萄糖、酵母提取物、碳酸钙（GYC）培养基筛选各种水果样品中的醋酸菌。添加溴甲酚绿的卡尔培养基用于区分醋酸杆菌属和葡萄糖杆菌属。将分离菌株接种于基础培养基中以筛选出高产醋酸菌株。通过生化试验、16S rRNA测序及限制性分析对分离菌株进行鉴定并构建系统发育树。基于最佳接种量、pH值、温度、搅拌、通气及培养基组成对细菌生长和产酸条件进行优化。
从醋酸杆菌属和葡萄糖杆菌属中分离出37株醋酸菌。产酸能力筛选出4株高产酸菌株。选取最高产酸菌株（产酸率10.03%）进行鉴定。16S rRNA测序及限制性分析显示该菌株为巴氏醋酸杆菌的一个变种（基因库登录号#GU059865）。产酸最佳条件为：培养基组成为2%葡萄糖、2%酵母提取物、3%乙醇和3%醋酸，接种量4%，生产培养基通气量3L/分钟。该菌株在12℃的GYC培养基中可保存一个多月，在-70℃可长期保存。
本研究结果表明分离出了一株本土醋酸菌。建议开展中试研究该菌株在醋酸生产中的应用潜力。
