Value added waste of Jatropha curcas residue: Optimization of protease production in solid state fermentation by Taguchi DOE methodology

The oil extraction of Jatropha curcas created the large amount of the by-product from its seeds. An application of solid-state fermentation (SSF) was considered to be of value to these raw materials. This study investigated the potential of a utilization of deoiled J. curcas seed cake as substrate for protease productions by Aspergillus oryzae. While various parameters for SSF was conventionally individually optimized, five parameters were simultaneously examined based on Taguchi method. The effect of three different levels of five factors, including moisture content of substrate, inoculums size, incubation temperature, type of porous substrate and incubation time were examined. The optimum conditions for the protease production by A. oryzae obtained from this experiment were 45% moisture content of substrate, 10% inoculums size, 30 °C incubation temperature, deoiled J. curcas seed cake mixed with cassava bagasse ratio 4:1 as porous substrate at 84 h of incubation time. By adjusting the conditions to these optimum levels, the protease production increased up to 4.6 times as many as the protease yield from the non-optimizing experiment. The use of statistical approach, Taguchi method, provided a satisfactory outcome in defining the optimum conditions for protease production by A. oryzae. Further, the utilization of deoiled J. curcas seed cake as substrate for SSF was proven as the suitable practice for this agricultural waste, in order to develop for an industrial use.     

利用泡盛曲霉产阿魏酸酯酶的研究

阿魏酸酯酶能水解多糖阿魏酸酯中的酯键,使阿魏酸游离出来。以麦麸、蔗渣、玉米皮作为碳源,采用3株泡盛曲霉(分别为40180、40384、2437)进行固体发酵,研究了产阿魏酸酯酶的活性(以去淀粉麦麸作为酶解底物)。结果表明,泡盛曲霉40180的产酶活力最高。其最佳培养基组分为:麦麸:蔗渣2:1(W:W),4%(NH4)2SO4,0.23%CuSO4,固液比1:1,在温度28℃下发酵3 d,酶活达到高峰(0.0679 U/g)。     

紫外线诱变黑曲霉提高产酶活力的研究(英文)

[目的]选育高产纤维素酶生产菌。[方法]以一株黑曲霉(Aspergillus niger)为出发菌株,经过紫外线(UV)诱变处理,选育出一株纤维素酶高产菌株生产菌。[结果]在适宜的条件下,选育得到的菌株2(15)产CMC活力最强,与出发菌株相比提高了近50%。[结论]今后应用于饲料生产中提供基础。     

一株扁座壳孢的分离及其胞外代谢产物对黄曲霉的抑制效果研究

研究座壳孢抗旱菌株Jos009的胞外代谢产物对食品污染菌黄曲霉的抗菌活性。利用体视显微镜观察子座的形状和颜色,以及通过切片方法获得各菌孢子大小和侧丝长度的详细数据来鉴定该菌株。提取Jos009的胞外代谢产物,并利用滤纸片法测定该菌胞外代谢产物对黄曲霉菌的抑制作用。从福建省建瓯市柑桔园采集到一株座壳孢菌株Jos009,通过分析其子座形态和分生孢子、侧丝等数据,可以鉴定Jos009是扁座壳孢（Aschersonia placeta Berk.et Br.）。其胞外代谢产物能明显抑制黄曲霉菌的生长,抑菌圈直径达17 mm。该菌在控制黄曲霉方面有良好的应用潜力,进一步研究很有可能从中分离到具有抑制黄曲霉的活性物质,将为防控黄曲霉菌污染,保障民生,提供候选药物资源。     

米曲霉AS 3.951发酵豆粕对大菱鲆摄食生长的影响

以初始平均体重2.07 ± 0.02g的大菱鲆（Scophthalmus maximus L.）为实验对象,进行为期70 d的摄食生长实验,研究不同添加水平的发酵和未发酵豆粕对大菱鲆摄食生长的影响。用米曲霉（Aspergillus oryzae）AS 3.951对豆粕进行固态发酵。经检测,与未发酵豆粕相比较,发酵豆粕中胰蛋白酶抑制因子、植酸、大豆皂甙、水苏糖和棉籽糖的含量分别下降了46.5％,26.6％、11.7％、30.1％和19.7％。实验共制作6种等氮等能的饲料,其中以全鱼粉饲料为对照饲料;未发酵豆粕蛋白分别替代25％、40％和55％的鱼粉蛋白;发酵豆粕蛋白分别替代40％和55％的鱼粉蛋白。结果表明,饲料中添加一定量的豆粕对大菱鲆的成活率没有显著的影响（P>0.05）。饲料中未发酵豆粕蛋白替代鱼粉蛋白的水平为25％时,对大菱鲆的摄食率、特定生长率、饲料效率和蛋白质效率均没有显著的影响,但替代水平为40％和55％时,以上指标显著降低（P<0.01）。饲料中发酵豆粕替代水平为40％时,未降低大菱鲆的摄食率、特定生长率、饲料效率和蛋白质效率,替代水平为55％时,显著降低大菱鲆的摄食率和特定生长率（P<0.01）。     

黑曲霉HQ-1液体发酵产纤维素酶条件研究

[目的]探讨黑曲霉HQ-1液体发酵产纤维素酶的最适条件。[方法]以1株产酶活力相对较高的黑曲霉HQ-1为出发菌株,采用单因子试验和正交试验对黑曲霉HQ-1液体发酵产纤维素酶的最适条件进行初步研究,并测定了CMC酶（CMCase）和滤纸酶（FPAase）的活力。[结果]影响黑曲霉HQ-1液体发酵产CMCase和FPAase的因素依次是复合碳源的含量、2种碳源的比例、氮源含量和装液量。该菌产CMCase的最适培养基为：麸皮＋玉米秸秆粉15‰（1：1）,NH4Cl2．0‰,其他成分同Mandel’s营养液;产FPAase的最适培养基为：麸皮＋玉米秸秆粉20‰（1：1）,NH4Cl1．5‰,其他成分同Mandel’s营养液。2种培养基的最适pH值和装液量均分别为5．0和50ml／250ml三角瓶。在30℃和170r／min下培养4d后,CMCase和FPAase达到525．2和217．6IU。[结论]该研究为纤维素酶生产菌株的研发提供一定的技术参考。     

毛竹根际新黑曲霉的解磷特性及促生作用

[目的]探究毛竹根际微生物新黑曲霉(Aspergillus neoniger)JXBR16对土壤难溶性磷酸盐的溶磷作用及对毛竹的促生效果。[方法]采用液体发酵培养法研究该菌株对Ca_3(PO_4)_2、CaHPO_4、FePO_4、AlPO_4和植酸钙等5种难溶性磷酸盐的溶解能力及碳源、氮源、pH、装液量和盐离子等因素对其解磷能力的影响;并采用温室盆栽法评价该菌株对毛竹实生幼苗的促生作用。[结果]表明,新黑曲霉对5种难溶性磷酸盐均具有较好的溶解能力,其中对FePO_4、CaHPO_4的溶解能力最佳,解磷量分别达3 208.31和3 027.09 mg·L~(-1);在碳源为蔗糖或葡萄糖、氮源为硫酸铵、初始pH值3.5、装液量2/5、温度25℃和盐离子浓度为0～1.0 g·L~(-1)条件下新黑曲霉的解磷能力最佳。施用该菌株180 d后毛竹根际土壤有效磷和矿质氮分别提高37%和41%,植株根、茎和叶磷含量分别提高了95%、102%和43%;毛竹地径、苗高和生物量分别比对照显著提高了44%、47%和50%。[结论]新黑曲霉能够有效增强南方红壤区毛竹林土壤磷的供给,促进植株养分吸收利用,并提高毛竹的生长,具有应用于竹林生物菌肥研制和开发的巨大潜力。     

Cellulase production by Aspergillus unguis in solid state fermentation

Lignocellulosic substrates are a good carbon source and provide rich growth media for a variety of microorganisms which prodLuce industrially important enzymes. Cellulases are a group of hydrolytic enzymes such as filter paperase (FPase), carboxymethyl cellulase(CMCase) andβ-glucosidase-responsible for release of sugars in the bioconversion of the lignocellulosic biomass into a variety of value-added products. This study examined cellulase production by a newly isolated Aspergillus unguis on individual lignocellulosic substrates in solid state fermentation (SSF). The maximum peak production of enzymes varied from one substrate to another, however,based on the next best solid support and local availability of groundnut fodder supported maximum enzyme yields compared with other solid supports used in this study.Groundnut fodder supported significant production of FPase (5.9 FPU/g of substrate), CMCase (1.1 U/g of substrate) andβ-glucosidase activity (6.5 U/g of substrate) in SSF. Considerable secretion of protein (27.0 mg/g of substrate) on groundnut fodder was recorded. Constant increment of protein content in groundnut fodder due to cultivation of A. unguis is an interesting observation and it has implications for the improvement of nutritive value of groundnut fodder for cattle.     

黑曲霉高产纤维素酶菌株的高通量筛选

以黑曲霉GSICC 60108为出发菌株,经紫外和电子束诱变处理后,采用纤维素-刚果红平板初筛和新建立的高通量微孔板法进行复筛以获得高产纤维素酶菌株.结果表明:试验得到1株稳定高产的纤维素酶菌株黑曲霉EBR-106;所建立的复筛方法的标准曲线在葡萄糖质量浓度为0～10 mg/mL的范围内线性良好(r=0.999 75)...     

Ear rot,aflatoxin accumulation,and fungal biomass in maize after inoculation with Aspergillus flavus

Aflatoxin, a toxin produced by the fungus Aspergillus flavus Link: Fries, occurs naturally in maize (Zea mays L.). Aflatoxin is a potent human carcinogen and is also toxic to livestock, pets, and wildlife. When contaminated with aflatoxin, the value of maize grain is markedly reduced. This investigation was conducted to compare ear rot, aflatoxin accumulation, and fungal biomass in maize single crosses with varying degrees of resistance to aflatoxin accumulation and to determine the relative importance of general combining ability (GCA) and specific combining ability (SCA) in the inheritance of resistance to ear rot, aflatoxin accumulation, and fungal biomass. Eight germplasm lines with different levels of resistance to aflatoxin accumulation were used as parents of a diallel cross. The cross was evaluated for visible ear rot, aflatoxin accumulation, and A. flavus infection in the grain. A. flavus infection was determined by quantitative real-time polymerase chain reaction (qRT-PCR) assays. Both GCA and SCA were significant sources of variation in the inheritance of the three traits although GCA accounted for a greater portion of the variation among single crosses. The interactions of GCA and SCA with years were highly significant for aflatoxin accumulation, but not significant for A. flavus infection. Estimates of GCA effects were highly significant for both reduced A. flavus infection and reduced aflatoxin accumulation for Mp313E, Mp715, and Mp717. Conversely, GCA effects associated with GA209 were significant for reduced levels of A. flavus infection and ear rot, but high levels of aflatoxin accumulation. Mp313E, Mp715, and Mp717 should be useful in breeding programs targeting both reduced levels of fungal infection and aflatoxin accumulation.