发酵时间和料水比对豆粕发酵的影响

采用凝结芽孢杆菌、枯草芽孢杆菌和酵母菌混合菌种发酵豆粕,研究发酵时间和料水比对发酵豆粕营养成分的影响,以确定豆粕适宜的发酵参数.结果表明:(1)与发酵48 h组比,发酵72 h组的(游离氨基酸+寡肽)/粗蛋白质极显著提高(P0.01),p H极显著降低(P0.01);(2)料水比为1∶0.70组的寡肽/粗蛋白质、游离氨基酸/粗蛋白和(游离氨基酸+寡肽)/粗蛋白质极显著高于料水比为1∶0.40和1∶0.55组(P0.01),p H极显著低于料水比为1∶0.40和1∶0.55组(P0.01),活菌数显著高于料水比为1∶0.40组(P0.05),多肽/粗蛋白质极显著高于料水比为1∶0.40组(P0.01).结论:采用凝结芽孢杆菌、枯草芽孢杆菌和酵母菌混合菌种发酵豆粕,其合理的发酵时间为72 h,料水比为1∶0.70.     

基于微生物电解池利用有机废弃物产氢研究进展

微生物电解池 (Microbial electrolysis cell,MEC) 技术作为一种新兴技术,实现了利用有机废水、农林废弃物、活性污泥等废物同步酶解发酵产氢的目的,有效提高了资源的综合利用效率。本文主要介绍了MEC 产氢的工作原理,分析了MEC 利用有机废弃物产氢过程中的影响因素。     

合丰42号大豆优质、高产栽培技术的研究

利用早熟高油大豆合丰42进行三种方式栽培,结果得出:合丰42平作窄行密植,行距30cm时,最佳密度为公顷保苗50-55万株;垄三栽培最佳密度为保苗35万株/hm2;穴播栽培产量和品质含量均最低,不适宜用于高油大豆合丰42栽培.合丰42优质、高产栽培最佳技术为平作窄行密植,其次是垄三栽培.     

Chemical changes during the fermentation of African locust-bean (Parkia filicoidea Welw) seeds for production of ‘Daddawa’

African locust-bean (Parkia filicoidea Welw) seeds were allowed to ferment under natural conditions and the chemical changes occurring during the fermentation were studied. Chemical analysis of fermented and unfermented beans showed a marked decrease in the total sugar content; crude and true protein levels all increased. The results of the chemical analyses indicate that fermentation resulted in protein enrichment of the fermented locust bean (daddaw). Fermentation also imparts a characteristic flavour and odour to the beans.     

The effect of cultivar on the rate and extent of combining pea straw degradability examined in vitro using the Reading Pressure Technique

Although about 225 000 t dry matter (DM) pea straw is produced annually in the UK, no recent data exist with respect to its nutritive value when offered to ruminants. This study, to examine field pea crop waste (straw) from 12 commercial cultivars of combining peas, was therefore undertaken when material grown as part of a European field pea network trial at Reading in 1998 was made available. The straw was subjected to chemical analysis and examined in vitro using the Reading Pressure Technique to generate gas production profiles and to determine both rate and extent of DM and organic matter degradation. Ash and crude protein (CP) concentrations (69 and 65 g kg^–1 DM) were generally lower than published values for legume straws but higher, especially CP, than cereal straws. Neutral‐detergent fibre concentrations were slightly lower, and metabolizable energy (ME) values, derived from degradable organic matter assessed in vitro (iOMD), higher than cereal straws, ranging from 6·0 to 8·1 MJ ME kg^–1 DM. Both cumulative gas production and rate of gas release varied significantly between cultivars, as did degradation with 96‐h iOMD values ranging from 468 to 602 g kg^–1. By combining these with the quantity of material harvested, ME yields for the different cultivars were found to range from 15 to 27 GJ ME ha^–1. Considerable, and general highly significant, variation was found between the cultivars examined, which may be used to rank straws with respect to their nutritive value. The cultivars Baccara and Solara followed by Athos and Vital were readily ranked higher than the other cultivars in terms of in vitro fermentation parameters and ME yields. These data suggest that pea straw, although often incorporated into the soil in post‐harvest operations, shows excellent potential as a ruminant forage feedstuff.     

醇化烟叶表面细菌筛选及增香效应研究

为明确烤烟醇化过程中烟叶表面增香微生物对其品质的作用,以6个不同产地的烟叶为试材,通过菌株分离和产酶能力筛选,对筛选出的细菌进行16S rDNA测序分析,将烟丝发酵样进行感官质量评吸、常规化学成分和多酚化合物分析。结果表明,菌株GY99处理样的感官评吸质量提升最为明显,能有效增加烟叶香气和甜感,其处理后的牡丹江、庆阳烟叶总分分别增加了2.26、2.03分,舒适度提升,香气质和香气量分别增加0.44、0.33分,刺激性和杂气降低。本研究筛选出1株可同时产蛋白酶、淀粉酶和纤维素酶的芽孢杆菌属(Bacillus sp.)菌株GY99。同时还筛选到3株可明显改善烟草品质的菌株,分别是芽孢杆菌属(Bacillus sp.)菌株GY96、假单胞菌属(Pseudomonas)菌株GY72和微球菌属(Micrococcus)菌株GY67。     

微波萃取-气相色谱法测定土壤中9种有机氯农药

[目的]建立测定土壤中9种有机氯农药的微波萃取-气相色谱法,为有机氯农药检测提供参考。[方法]微波萃取-氟罗里硅土固相小柱净化同时提取土壤中9种有机氯农药污染物,利用气相色谱电子捕获检测器(ECD)检测样品。[结果]9种有机氯污染物平均回收率为78.9%~114.1%;方法检出限为0.27~0.56μg/kg,精密度(RSD)为2.48%~4.75%。[结论]利用微波法提取不仅可节省时间、提高效率,而且能获得较高的回收率。     

朱砂叶螨乙酰胆碱酯酶的表达纯化及其酶活测定条件优化

乙酰胆碱酯酶(Acetylcholinesterase,AChE)是生物体内保证神经信号正常传递的关键酶,是有机磷和氨基甲酸酯类农药的作用靶标。现研究拟采用发酵罐培养含pET-30a/ace的表达菌株E.coli BL21(DE3),大量表达纯化螨AChE,利用单因素试验和正交试验优化AChE活性的测定条件。结果表明:发酵培养的重组菌株大量表达约为68kD的朱砂叶螨AChE蛋白。底物浓度、温度、pH和酶浓度等各测定因素对朱砂叶螨乙酰胆碱酯酶活性存在显著影响。确定朱砂叶螨乙酰胆碱酯酶活性测定的最佳反应条件为:底物浓度1mmol/L,pH值7,温度35℃,酶浓度0.5mg/mL。通过体外发酵培养纯化获得了大量的朱砂叶螨AChE重组蛋白,确定了螨AChE活性测定的最佳条件,为进一步研究其酶学性质以及AChE抑制剂的体外筛选奠定基础。     

毕赤酵母产人源丁酰胆碱酯酶的发酵条件优化

测定不同条件下重组毕赤酵母的蛋白表达量及酶活力,优选毕赤酵母分泌表达人源丁酰胆碱酯酶的发酵条件。在单因素试验的基础上,采用响应面法优化表达条件,确定了毕赤酵母分泌表达人源丁酰胆碱酯酶的最佳发酵条件:发酵时间4.8d,甲醇浓度13.90%,甘油浓度2.1%。使用最佳发酵条件对毕赤酵母进行培养,最终得到的人源丁酰胆碱酯酶的表达量为368.2mg/L,表达量提高了27%。     

高温分解与乳酸菌分步发酵提高秸秆饲料消化率及适口性

以提高秸秆饲料的消化率和适口性为目的,该研究1)以干玉米秸秆为材料,接种木质纤维素分解菌复合系WDC2,进行高温分解发酵;2)以乳酸菌复合系SFC-2为接种物,进行乳酸菌液体发酵;3)将乳酸菌发酵液以质量体积比1∶1比例均匀喷洒到发酵秸秆中,制备发酵秸秆饲料。该研究从营养学和分子生态学角度探讨了高温分解与乳酸菌分步发酵提高秸秆饲料消化率和及适口性的可行性。结果表明,经高温分解发酵,秸秆中微生物多样性丰富,不含致病菌。以南阳黄牛为研究对象,秸秆的干物质、中性洗涤纤维和酸性洗涤纤维体外消化率分别提高了13.94%、22.56%和21.12%,采食量提高21.71%;部分分解的秸秆经乳酸菌发酵液吸附后,粗蛋白增加36.17%。秸秆的高温分解发酵与乳酸菌的乳酸发酵相结合的饲料制作工艺,即提高了秸秆的消化率和营养价值,也改善了秸秆的适口性。