Enzymatic synthesis of fatty alcohol esters by alcoholysis

Lipase-catalyzed conversions of some minor oils and fats like mowrah (Madhuca latifolia), mango (Mangifera indica) kernel, and sal (Shorea robusta) fats into low, medium, and high molecular weight alcohol esters have been investigated. In solvent-free medium, alcoholysis of the above-mentioned fats with 10% (w/w) Mucor miehei lipase produced alcohol esters in good yield. The percentage molar conversions of C₄, C₈, C₁₀, C₁₂, C₁₄, C₁₆, C₁₈, and C_18:1 alcohols into corresponding alcohol esters ranged from 86.8 to 99.2, while the percentage molar conversions on the basis of oil were in the range of 108.0 to 123.5.     

不对称还原4’-甲基苯乙酮微生物的筛选及反应条件优化

从土壤中筛选得到一株能将4’-甲基苯乙酮高效不对称还原为S-4’-甲基-1-苯乙醇的菌株T19,T19采用16SrDNA进行分子生物学鉴定,被鉴定为卷枝毛霉菌(Mucor circinelloides)。研究表明,在体系pH为6～7,反应温度30℃的条件下,添加50g/L的葡萄糖为辅助底物,底物4’-甲基苯乙酮的加入量为3g/L,反应3d后,产物S-4’-甲基-1-苯乙醇的得率最高可达92.6%,对映体过量值(e.e.)达到100%。     

响应面法优化微小毛霉固态发酵生产凝乳酶工艺研究

采用麦麸培养基进行固态发酵,以研究发酵条件对产酶活力的影响,在此基础上应用Plackett-Burman、最陡爬坡实验和Box-Behnken实验设计,对微小毛霉的固态发酵培养基进化以达到最佳产酶量。实验结果表明,最佳发酵条件为:发酵时间5d,发酵温度30℃,固液比值0.75,接种量为3份,测得凝乳酶酶活为828U/mL。并且当麸皮质量为15.50g、(NH4)2SO4质量为0.15g、KH2PO4质量为0.08g时,微小毛霉产凝乳酶活力达到1200U/mL。较未优化前活力提高了66.67%。     

Enzymatic Glycerolysis of Palm and Palm Kernel Oils

Glycerolysis of palm and palm kernel oils were carried out using commercial lipases from Candida antarctica (Novozym 435) and Mucor miehei (Novozym 388) as catalyst (500 units lipase/g oil) at 40°C and with an oil:glycerol molar ratio of 1:2 in a solvent-free system. Novozym 435 catalyzed the glycerolysis of palm and palm kernel oils giving reaction products in similar compositions. Partial acylglycerols contents of the glycerolysis products obtained from palm and palm kernel oils were 64% (wt) and 66% (wt), respectively. However, partial acylglycerols contents of the glycerolysis products obtained from palm and palm kernel oils conducted with Novozym 388 as catalyst at the same conditions were 44% (wt) and 56% (wt), respectively. On the other hand, free fatty acid contents of the glycerolysis products of palm and palm kernel oils obtained using Novozym 388 were higher, 25–30% (wt), than those obtained by Novozym 435, 4–5% (wt). The monoacylglycerols fraction with the highest content of oleic acid, 62.7% (wt), was obtained from the palm kernel oil glycerolysis reaction catalyzed by Novozym 435.     

微生物Mucor sp.转化肉桂酸生成苯乙酮降解途径分析

利用GC-MS检测Mucor sp.转化肉桂酸的产物,对微生物Mucor sp.降解肉桂酸的途径进行了分析。β-苯乙醇首次作为微生物Mucor sp.转化肉桂酸生成苯乙酮的中间体在产物中被检测到。Mucor sp.降解肉桂酸的途径是:在肉桂酸的侧链双键上先发生环氧化反应得到3-苯基-2,3-环氧丙酸,环氧化合物经脱羧、还原开环得到中间体β-苯乙醇,β-苯乙醇经羟基转移和进一步催化氧化生成苯乙酮。     

Enzymatic Glycerolysis of Palm and Palm Kernel Oils

Glycerolysis of palm and palm kernel oils were carried out using commercial lipases from Candida antarctica (Novozym 435) and Mucor miehei (Novozym 388) as catalyst (500 units lipase/g oil) at 40°C and with an oil:glycerol molar ratio of 1:2 in a solvent-free system. Novozym 435 catalyzed the glycerolysis of palm and palm kernel oils giving reaction products in similar compositions. Partial acylglycerols contents of the glycerolysis products obtained from palm and palm kernel oils were 64% (wt) and 66% (wt), respectively. However, partial acylglycerols contents of the glycerolysis products obtained from palm and palm kernel oils conducted with Novozym 388 as catalyst at the same conditions were 44% (wt) and 56% (wt), respectively. On the other hand, free fatty acid contents of the glycerolysis products of palm and palm kernel oils obtained using Novozym 388 were higher, 25-30% (wt), than those obtained by Novozym 435, 4-5% (wt). The monoacylglycerols fraction with the highest content of oleic acid, 62.7% (wt), was obtained from the palm kernel oil glycerolysis reaction catalyzed by Novozym 435.     

绍兴腐乳毛坯中蛋白酶的检测

１．７５％ＮａＣｌ溶液可有效抽提林木毛霉菌丝体表面的蛋白酶，依此确立了腐乳毛坯中蛋白酶的检测法。该酶系在４０％以下２ｈ酶活稳定不变，６０℃ｌｈ能保持５８％活力；其最适作用温度和ｐＨ分别为５５～６０℃和６～７ｐＨ；ｐＨ稳定范围为４～７；ＮａＣｌ和ＣＨ＿３ＣＨ＿２ＯＨ对酶系有明显的保护作用。讨论了蛋白酶检测及其性质对腐乳工艺改进的指导意义。     

Optimisation of enzymatic esterification of soybean oil deodoriser distillate

The enzymatic esterification of free fatty acids from soybean oil deodoriser distillate with ethanol, catalysed by immobilised fungal lipase, was studied. The extent of conversion of free fatty acids to ethyl esters was optimised using a response surface methodology obtained through a second‐order factorial experimental design. The variables studied were reaction temperature (30–70 °C), enzyme concentration (7–23%) and ethanol/free fatty acid molar ratio (0.3–3.7:1). The optimal reaction conditions achieved were temperature from 46.4 to 53.6 °C, enzyme concentration from 13.6 to 16.5% and ethanol/free fatty acid molar ratio from 1.7 to 2.3:1, with conversions above 88%. No significant tocopherol losses were observed during the process. In conclusion, enzymatic fatty acid esterification was shown to be a technically viable process. © 2001 Society of Chemical Industry     

表面毛霉成熟干酪制备工艺优化

利用从毛豆腐中分离得到的一株毛霉属菌株,制备得到表面毛霉成熟干酪,并在干酪生产过程中采用乳酸预酸化的方式避免了常规乳酸菌发酵剂对毛霉干酪成熟的影响。单因素实验确定牛乳预酸化pH为5.7,氯化钙添加量0.02%,凝乳酶的添加量为0.0035%,凝固温度33℃,毛霉孢子悬浮液浓度为1×104～1×105cfu.mL-1。     

从总状毛霉中超声波提取壳聚糖的工艺研究

采用超声波提取方法,对壳聚糖的提取工艺进行研究。其最适提取方法:将菌体放入浓度为0.8mol/L的NaOH碱液浸泡,菌丝体和碱液体积比为1∶30(w/v),加热至50℃超声波400W处理时间50min,再经过离心取沉淀、水洗、离心,2%乙酸95℃加热萃取12h,得壳聚糖溶液,经过中和沉淀,再经过真空干燥得壳聚糖,最高得率为16.5%。其干菌丝体壳聚糖的得率和优化前相比较得到了进一步的提高。