Optimization for microbial degradation of petroleum hydrocarbon (TPH) by Enterobacter sp. S-1 using response surface methodology

In this research, the response surface method designed by Box-Behnken was used to study the effect of temperature, pH value and TPH concentration on the biodegradation of Enterobacter sp. S-1contaminated soil. The value of determination coefficient (R²=0.9565) by analysis of variance (ANOVA) indicated a satisfactory agreement between the quadratic model and the experimental data. It was found that TPH degradation rate was more significantly affected (P?<?0.0006) by temperature compared with other two parameters. In the temperature of 30?°C, pH value of 7.14 and TPH concentration was 4.83?g/L, the best degradation rate was 81.63%.     

大曲中产酱香芽孢杆菌的筛选及其代谢产香探析

对茅台酒生产各环节所采集的28个样品进行了初步分析,从高温大曲制作过程的不同环节筛选出芽孢杆菌104株,用麦曲模仿升温发酵筛选产香的菌株,经鉴定分别为枯草芽孢杆菌、解淀粉芽孢杆菌、地衣芽孢杆菌等,其中产酱香优良的菌株25株,分为多种香味,与不产香型的细菌对比,产酱香的25株均能产生二乙酰、乙偶姻、蛋白酶、淀粉酶等,结合茅台的生产流程分析了其产香的可能机制,得到结论：芽孢杆菌在大曲发酵过程中产生蛋白酶和淀粉酶等多种酶类和代谢物质,进而在高温、偏酸环境下通过美拉德反应产生吡嗪等多种茅台酒特征香味物质。     

白腐菌预处理甘蔗渣促进水解的研究

利用一株产木质素降解酶的白腐菌Ceripriopsis sp.,以固态发酵形式对甘蔗渣进行预处理,选择性降解其中的木质素,从而提高其水解效率。甘蔗渣固态发酵过程中,发酵温度、培养基成分、含水量和初始pH值对酶活和糖收率都有影响。含水量是对糖收率影响最大的因素,其次是麸皮添加量,再次是温度,而初始pH值影响最小。甘蔗渣固态发酵的最佳条件为:培养基中含水量为80%,麸皮含量为5%,初始pH=4.0时28℃发酵14d,获得的糖产率最大,达20.6%。     

响应面法优化硇洲马尾藻多糖提取工艺

为优化硇洲马尾藻多糖提取工艺,在单因素试验基础上,选择提取温度,提取时间,料液比为自变量,多糖提取率为响应值,利用Box-Benhnken中心组合试验和响应面分析法,研究各自变量交互作用及其对硇洲马尾藻多糖得率的影响,模拟得到二次多项式回归方程的预测模型,并确定硇洲马尾藻多糖提取工艺最佳条件为:料液比为1:21(g/mL),提取温度为90.7℃,提取时间为5.14 h,在此条件下,硇洲马尾藻多糖得率达到6.39%。     

Antioxidant capacity and phenolic compounds in commercially grown native Australian herbs and spices

The antioxidant capacities and phenolic composition in six native, commercially grown, Australian herbs and spices were investigated. Tasmannia pepper leaf, followed by anise myrtle and lemon myrtle contained the highest levels of total phenolics (TP; 102.1; 55.9 and 31.4 mg gallic acid equivalents (GAE)/g dry weight (DW), respectively). Tasmannia pepper leaf exhibited the highest oxygen radical absorbance capacity (ORAC assay) followed by lemon myrtle and anise myrtle. Anise myrtle exhibited the highest total reducing capacity [TRC; Ferric Reducing Antioxidant Power (FRAP) assay], followed by Tasmannia pepper leaf and lemon myrtle. Australian bush tomato, with TP content of 12.4 ± 0.9 mg GAE/gDW and TRC of 206.2 μMol Fe⁺²/gDW, resembled the Chinese Barbary Wolfberry fruit. The TP content of Tasmannia pepper berry (16.86 mg GAE/gDW) was similar to that of black pepper, but it’s TRC was 25% lower. Cinnamic acids and flavonoids, tentatively identified by mass spectrometry, were identified as the main sources of antioxidant activities.     

枯草芽孢杆菌纤溶酶的纯化及性质研究

以从牛肉酱中筛选的1株高产纤溶酶的枯草芽孢杆菌为材料,进行发酵产酶。其发酵液经过硫酸铵盐析、Sephadex G-100凝胶过滤、C M SepharoseCL-6B离子交换层析和电泳制备,得到电泳纯的枯草芽孢杆菌纤溶酶;其分子质量为32.5ku;pI10.9～11.8;具有直接溶解纤维蛋白和激活纤溶酶原的双重作用;胰蛋白酶对此酶无降解作用,对其纤溶活性无影响;该酶在pH4.0～13.0稳定,对温度的适应范围较广。     

一株转化茴脑生成茴香醛的菌株筛选与鉴定

以反式茴脑为惟一碳源,通过富集培养和分离纯化,从环境中筛选到320株能以反式茴脑作为惟一碳源的菌株.经薄层层析法、紫外分光光度法和气相色谱法相结合对转化液进行分析,结果获得一株相对高产茴香醛的细菌菌株WGB30.该菌最适生长温度28℃,最适pH 6.5,在复筛培养基中,30℃摇床200 r/min培养12h可达到对数期,在培养60 h时茴香醛的摩尔转化率达5.08％.综合形态学、生理生化实验、Biolog EcoPlates鉴定和16SrDNA序列分析结果,将菌株WGB30鉴定为伯克霍尔德氏菌(Burkholderia sp.).     

变温调控破囊壶菌发酵生产二十二碳六烯酸

破囊壶菌Aurantiochytrium sp.细胞生长、油脂积累及二十二碳六烯酸(docosahexaenoic acid,DHA)合成与培养温度密切相关.该研究在摇瓶中考察了不同温度对破囊壶菌发酵的影响,结果表明,20～35℃的培养温度较利于破囊壶菌细胞的生长,而25～28℃的培养温度利于油脂的积累;虽然15℃培养...     

头孢霉AL031真菌固体发酵产物抗氧化、抑菌活性研究

基于原有固体发酵条件,以提取物清除DPPH自由基的能力为评价指标,探讨头孢霉AL031真菌固体发酵的最佳时间和次生代谢产物的提取条件。用DPPH法和光敏化合物微生物法测定其次生代谢产物的抗氧化活性,微生物纸片法测定其抑菌活性。结果表明:头孢霉AL031真菌固体发酵的最佳培养时间为9d,最佳提取条件为以乙酸乙酯浸泡,其提取物对DPPH自由基的EC50为5.84μg/mL,光敏化合物微生物法亦证明其具有良好的抗氧化活性。抑菌实验表明头孢霉AL031真菌的次生代谢产物具有广谱抑菌作用。     

优良发酵剂的筛选鉴定及菌株生长条件优化的研究

从泡菜中分离出菌株,利用钙溶圈筛选乳酸菌。经低温发酵能力测试筛选出优良菌株并接种于鸡肉发酵验证,得到发酵特性优良的菌株三株。根据生化鉴定和16S rDNA序列测序所得菌株为两株乳杆菌(Lact.1、Lact.2)和一株清酒乳杆菌(Lact.3)。以OD值为指标,以pH值、温度、葡萄糖添加量和接种量作为参考因素,利用正交试验优化确定两株乳杆菌(Lact.1、Lact.2)和清酒乳杆菌生长最优条件分别为pH7.0、温度35℃、葡萄糖添加量4%、接种量3%;pH7.0、温度35℃、葡萄糖添加量2%、接种量3%和pH6.0、温度32℃、葡萄糖添加量2%、接种量1%。