Investigation of the use of ram horn hydrolysate for fungal protein production

Production of the fungus Aspergillus niger NRRL 330 was studied in submerged fermentation with ram horn hydrolysate (RHH) as substrate. The characteristics of RHH have been reported previously. The RHH was enriched by addition of glucose and KH₂PO₄. The effects of kinetic parameters on the biomass yield of the fungus were investigated. The optimal conditions for growth of A niger on RHH were initial pH 6.5, temperature 30 °C, fermentation time 96 h and agitation speed 150 rpm. Under these optimal conditions the initial carbohydrate content of RHH was reduced from 1.52 to 0.2% and the biomass yield was 8.9 g l^?1. The biomass contained about 48.1% protein, 5.2% fat and 9.4% ash (on a dry weight basis). The amino acid content of the biomass was compared with Food and Agricultural Organisation (FAO) and animal feed standards. The protein produced contained all the essential amino acids for animal feed, but the amounts of these amino acids were somewhat lower than those of FAO and soybean reference protein. However, the amino acid composition of the biomass was better than that of animal feed. The results with RHH were also compared with previously reported data on fungal mycelium grown on waste liquor substrate. In conclusion, it was found that RHH could be used as a substrate in the production of fungal protein for use as animal feed. Copyright © 2003 Society of Chemical Industry     

The influence of the ion content of whey on the pH-activity profile of the β-galactosidase from Aspergillus oryzae

The pH-dependence of the reaction kinetics of lactase (β-galactosidase) from Aspergillus oryzae in different reaction media is presented in terms of a two-parameter model. The lactase from A. oryzae seems to have replaced the A. niger lactase on the market owing to a better activity/price ratio and may be utilised for lactose hydrolysis in acid as well as in neutral milk products. Its pH optimum is around pH 4.5. However, in the neutral pH-range its activity depended strongly on the salt content of the substrate solution. For example, its activity in whey (pH 6.5) fell to only 30% of its expected activity in a pure lactose solution at the same pH. The whey effect was the same for both soluble and immobilised lactase. The two parameter kinetic model, which included a term for competitive product inhibition gave excellent agreement with experimental data, and may thus be useful for the prediction of reactor performance with this enzyme.     

转盘反应器固定米根霉的L－乳酸发酵

研究了米根霉的固定化方法，研制了用吸附法固定米根霉的生物转盘反应器，考察了在该反应器中培养基组成及其它操作条件对Ｌ－乳酸发酵的影响。实验结果表明，应用吸附法固定化的米根霉及生物转盘反应器进行Ｌ－乳酸发酵具有发酵速率快，Ｌ－乳酸得率高及既能用于连续发酵又能用于间歇发酵等优点     

米曲霉在牛乳中最适生长条件的研究

利用米曲霉对牛乳进行发酵,通过单因子及正交试验以菌丝体干重为指标对其在牛乳中的生长进行了研究．结果表明：接种量为4％,装液量为30mL,摇床转速为180r／min时菌丝体干重可达到最大．此外测得最大菌丝体干重时的蛋白质分解率可达35．6％．     

酱油曲菌的选择及酱油发酵条件

研究了日本酱油生产菌AspergillusoryzaeJP DQ 1,AspergillusoryzaeJP W和我国酱油生产菌AspergillusoryzaeAS3.951的酶系。结果表明:3种菌在浓酱油曲和白酱油曲培养基上均可产生α 淀粉酶、糖化酶、纤维素外切酶、果胶酶、酸性蛋白酶和中性蛋白酶;JP W是较好的白酱油生产菌,JP DQ 1是较好的浓酱油生产菌。还对酱油酵母的生理特性进行了部分研究,发现食盐浓度对酱油酵母生长影响较大,酱油发酵过程的盐浓度不宜超过3mol／L,低于2mol／L更佳。酱油酵母的较适生长pH为4.5～5.5。     

Regulation of Autophagy Machinery in Magnaporthe oryzae

Plant diseases cause substantial loss to crops all over the world, reducing the quality and quantity of agricultural goods significantly. One of the world’s most damaging plant diseases, rice blast poses a substantial threat to global food security. Magnaporthe oryzae causes rice blast disease, which challenges world food security by causing substantial damage in rice production annually. Autophagy is an evolutionarily conserved breakdown and recycling system in eukaryotes that regulate homeostasis, stress adaption, and programmed cell death. Recently, new studies found that the autophagy process plays a vital role in the pathogenicity of M. oryzae and the regulation mechanisms are gradually clarified. Here we present a brief summary of the recent advances, concentrating on the new findings of autophagy regulation mechanisms and summarize some autophagy-related techniques in rice blast fungus. This review will help readers to better understand the relationship between autophagy and the virulence of plant pathogenic fungi.     

米根霉发酵对脱脂薏米麸皮营养组成及抗氧化活性的影响

研究米根霉发酵对脱脂薏米麸皮游离氨基酸、多肽、多酚、黄酮、酚类物质组成及抗氧化活性的影响.结果表明,脱脂薏米麸皮在发酵过程中总游离氨基酸含量逐渐增加,低分子量多肽比例逐渐提高.脱脂薏米麸皮的游离型多酚和黄酮含量在发酵过程中呈逐渐上升的趋势,72 h后分别较发酵前提高了111.7％和168.6％(P＜0.05),而结合型...     

真菌发酵预处理麻疯树籽高效提油初步研究

利用真菌固液态发酵麻疯树籽,通过测定还原糖和氨态氮含量变化,判断真菌对营养成份利用情况与油脂提取效果关系。实验结果表明,经黑曲霉固液态发酵预处理麻疯树籽在发酵48 h得到最大提油量,分别为32.75%(w/w)和31.95%(w/w),比对照组(27.5%,w/w)分别提高19.1%和16.2%;补充适量葡萄糖后有利于提高提油量,经黑曲霉固液态发酵预处理麻疯树籽都在发酵72 h后达最大提油量,分别为35.75%(w/w)和34.65%(w/w),比对照组(27.5%,w/w)分别提高30%和26%。经实验,黄曲霉不适于麻疯树籽发酵,发酵后提油效果没明显提高。     

反相HPLC双检测器法同时测定米根霉乳酸发酵液中的有机酸与葡萄糖

提出了用高效液相色谱法同时测定米根霉乳酸发酵液中的有机酸和葡萄糖。用Ｗａｋｏｓｉ－Ⅱ５Ｃ１８ＲＳ（４．６ｍｍ＊１５０ｍｍ,５μｍ）色谱柱,以０．０１ｍｏｌ／Ｌ磷酸水溶液（ＰＨ２．５）为流动相,流速１ｍｌ／ｍｉｎ,利用有机酸及葡萄糖对紫外光吸收强弱的差异,采用双检测器系统,以示差折光检测器检测葡萄糖,以可变波长检测器检测有机酸,一次进样可同时定性及定量分析待测样中的有机酸及葡萄糖,每个样品的分析过程     

Characteristics of L-lactic Acid Production byRhizopus oryzae mutant RL6041

A high-yield mutant strain Rhizopus oryzae RL6041 induced by ions implantation was used in the present study. L (+)-lactic acid was generated by RL6041 grown on liquefied corn starch as a substrate. With optimal conditions (Liquefied corn starch 150g/L, (NH₄)₂SO₄ 2.0g/L, MgSO₄·7H₂O 1.0g/L, ZnSO₄·7H₂O 2g/L, KH₂PO₄ 0.2g/L, CaCO₃ 8%, medium size 20/250Ml, seed age 6h, fermentation temperature 38° C), the yield of L (+)-lactic acid in shake-flask reached 133～136g/L after 36h, indicating that the conversion rate was as high as 88%～91%, and the productivity was 3.75g/L·h. There was almost a 70% increase in lactic acid production compared with the original strain RE3303.