Detoxification of corn stover and corn starch pyrolysis liquors by ligninolytic enzymes of Phanerochaete chrysosporium

Phanerochaete chrysosporium (ATCC 24725) shake flask culture with 3 mM veratryl alcohol addition on day 3 was able to grow and detoxify different concentrations of diluted corn stover (Dcs) and diluted corn starch (Dst) pyrolysis liquors [10, 25, and 50% (v/v)] in defined media. GC-MS analysis of reaction products showed a decrease and change in some compounds. In addition, the total phenolic assay with Dcs samples demonstrated a decrease in the phenolic compounds. A bioassay employing Lactobacillus casei growth and lactic acid production was developed to confirm the removal of toxic compounds from 10 and 25% (v/v) Dcs and Dst by the lignolytic enzymes, but not from 50% (v/v) Dcs and Dst. The removal did not occur when sodium azide or cycloheximide was added to Ph. chrysosporium culture media, confirming the participation of lignolytic enzymes in the detoxification process. A concentrated enzyme preparation decreased the phenolic compounds in 10% (v/v) corn stover and corn starch pyrolysis liquors to the same extent as the fungal cultures.     

Degradation of isoproturon by the white rot fungus Phanerochaete chrysosporium

The ability of the white rot fungus Phanerochaete chrysosporium to degrade isoproturon was tested in solid substrate fermentation (SSF) cultures using straw as substrate/carrier material. The role of the lignin degrading enzymes, lignin peroxidase (LiP) and manganese peroxidase (MnP), in the degradation of the herbicide was also studied. Isoproturon concentration and LiP and MnP activities were followed in sterile straw cultures of the fungus. In vitro degradation tests with pure LiP and MnP were performed. P. chrysosporium in straw cultures was able to degrade 91% of the herbicide isoproturon in 14 days of incubation. A sharp decrease of isoproturon coincided with the largest MnP activity. Although LiP activity was also present, its role in SSF is unclear. The in vitro tests showed a strong isoproturon oxidation by LiP and a slower oxidation by MnP in the presence of Tween 80 probably by a lipid peroxidation process. Two N-demethylated metabolites were identified in pure enzyme tests and in SSF cultures. Several unidentified isoproturon derivatives, most likely hydroxylated, were also formed in both systems. The different pattern of derivatives detected in pure LiP and MnP tests showed a completely different metabolism by these two enzymes.     

玉米秸秆酶解上清液厌氧发酵产氢工艺优化

该文主要以粒度小于0.088 mm秸秆粉的酶解上清液为底物与热预处理后的活性污泥进行厌氧发酵产氢试验,以累积产氢量为考察指标,基于响应面Box-Behnken模型研究不同影响因素对玉米秸秆酶解上清液厌氧发酵产氢的影响,对玉米秸秆酶解上清液厌氧发酵产氢工艺进行优化。结果表明:温度、初始p H值和还原糖浓度三因素中,温度和还原糖浓度对玉米秸秆酶解上清液厌氧发酵产氢的影响最大。采用Box-Behnken模型获得的最佳产氢条件为:温度38.32℃,初始p H值4.93,还原糖浓度20.70 mg/m L,最大产氢量685.59 m L,此时最大产氢率为57.13 m L/g(玉米秸秆)。通过试验验证,实际最大产氢量为659.24 m L,产氢率为54.94 m L/g(玉米秸秆),与模型预测值相比,相对误差为3.84%,说明该模型具有较好的拟合性。该优化工艺可为后期连续流状态下的生物制氢系统提供参考。     

酶法复合脱毒提高玉米秸秆水解液丁醇发酵效率

利用玉米秸秆发酵产丁醇在生物质转化领域具有明显优势。为解除玉米秸秆水解液中多种有毒物质对微生物生长的抑制及对发酵产量的影响,该研究摒除常用的理化脱毒法,选择高效环保的酶法脱毒以实现溶剂高产。研究结果表明:通过优化漆酶和甲酸脱氢酶添加量以去除水解液中酚类和甲酸,单独添加漆酶5 U/m L、甲酸脱氢酶1 U/m L,水解液发酵的丙酮-丁醇-乙醇(acetone-butanol-ethanol,ABE,总溶剂)产量分别为1.03和1.11 g/L。再在活性炭的辅助下形成高效酶法复合脱毒体系,经复合脱毒处理的水解液发酵后丁醇产量达2.90 g/L,总溶剂ABE产量达到4.4 g/L,比未作处理的对照组发酵产量高出约5倍,实现了生物质的高效转化。可为玉米秸秆水解液发酵生产燃料丁醇提供参考。     

Comparative Analysis of Azo Dye Biodegradation by Aspergillus oryzae and Phanerochaete chrysosporium

The paper reports ultraviolet matrix-assisted laser desorption/ionization mass spectroscopy (UVMALDI-MS) protocol for determination of complex heterogeneous emulsion or suspension formulations. The active agents and surfactants are morpholine fungicide fenpropimorph (1), amorolfine (2), tridemorph (mixture of 2,6-dimethyl-4-alkylmorpholins 3–6), 2,6-dimethyl-4-[2-methyl-3-(6-methyl-decahydro-naphthalen-2-yl)-propyl]-morpholine (7), dodemorph (8), main metabolite of 1 fenpropimorph acid (9), sodium dodecyl sulfate (10), and stearate (11). The full method and techniques validation as well as method performance parameters are discussed in terms of their maximal representativeness toward real environmental and foodstuff assay problems. These are additionally complicated by heterogeneous laterally, vertically, and time distribution of pesticide contaminants and their major metabolites in environmental samples. The real environmental heterogeneous distribution is elucidated, studying sterilized soil fractions with particle size 2.0 μm, clay content 11.5 %, silt 23.0 %, sand 8.1 %, and pH?∈ 6.0–8.1. A statistical sampling cluster approach is used. The method performance parameters are concentration LODs of 0.026 mg kg^?1 (res. LOQs 0.08666 mg kg^?1). Concentration linear dynamic ranges are ∈?0.025–7.3 mg kg^?1 (r ²?=?0.99822 and 0.99421) and ∈?2.3–7.4 mg kg^?1 (level of confidence of 99.33₁?%) for complex spiked heterogeneous soil samples. The data illustrates the great capability of method and its promising application for environmental contamination monitoring and controlling programs for assessment.     

汽爆玉米秸秆同步糖化发酵产乙醇的工艺优化

该文对同步糖化发酵玉米秸秆生产纤维乙醇的工艺条件进行了研究,分别利用单因素试验和正交试验考察了影响发酵的工艺条件。结果显示：温度37℃、pH值4.8、底物15%（质量分数）、表面活性剂Tween-20 0.15%（质量分数）、纤维素酶用量30 U/g、酵母用2%的葡萄糖溶液活化,接种量5‰（相对底物干质量）、培养基的组成：KH2PO4 2.5 g/L,(NH4)2SO4 2.0 g/L,MgSO4·7H2O 0.15 g/L,CaCl2 0.35 g/L、发酵时间60 h为同步糖化发酵（SSF）生产乙醇的最优工艺条件,该条件下乙醇的体积分数为2.85%,乙醇得率达理论值的88.12%。     

Enzyme production by wood-rot and soft-rot fungi cultivated on corn fiber followed by simultaneous saccharification and fermentation

This research aims at developing a biorefinery platform to convert lignocellulosic corn fiber into fermentable sugars at a moderate temperature (37 °C) with minimal use of chemicals. White-rot (Phanerochaete chrysosporium), brown-rot (Gloeophyllum trabeum), and soft-rot (Trichoderma reesei) fungi were used for in situ enzyme production to hydrolyze cellulosic and hemicellulosic components of corn fiber into fermentable sugars. Solid-substrate fermentation of corn fiber by either white- or brown-rot fungi followed by simultaneous saccharification and fermentation (SSF) with coculture of Saccharomyces cerevisiae has shown a possibility of enhancing wood rot saccharification of corn fiber for ethanol fermentation. The laboratory-scale fungal saccharification and fermentation process incorporated in situ cellulolytic enzyme induction, which enhanced overall enzymatic hydrolysis of hemi/cellulose components of corn fiber into simple sugars (mono-, di-, and trisaccharides). The yeast fermentation of the hydrolyzate yielded 7.8, 8.6, and 4.9 g ethanol per 100 g corn fiber when saccharified with the white-, brown-, and soft-rot fungi, respectively. The highest ethanol yield (8.6 g ethanol per 100 g initial corn fiber) is equivalent to 35% of the theoretical ethanol yield from starch and cellulose in corn fiber. This research has significant commercial potential to increase net ethanol production per bushel of corn through the utilization of corn fiber. There is also a great research opportunity to evaluate the remaining biomass residue (enriched with fungal protein) as animal feed.     

Ligninolytic enzyme production by Phanerochaete chrysosporium in plastic composite support biofilm stirred tank bioreactors

Phanerochaete chrysosporium (ATCC 24725) produced lignin peroxidase (LiP) and manganese peroxidase (MnP) in defined medium in plastic composite support (PCS) biofilm stirred tank reactors. Laccase was not detected. The formation of the Ph. chrysosporium biofilm on the PCS was essential for the production of MnP and LiP. The bioreactor was operated as a repeat batch, and no reinoculation was required between batches. Peroxidase production was influenced by 5 min purging of the bioreactor with pure oxygen or continuous aerating with a mixture of air and oxygen at a flow rate of 0.005 vvm. Continuous aeration and 300 rpm agitation with 3 mM veratryl alcohol addition on days 0 and 3 demonstrated the highest lignin peroxidase production on day 6 with means of 50.0 and 47.0 U/L. Addition of veratryl alcohol and MnSO(4) on day 0 with 300 rpm agitation and continuous aeration at 0.005 vvm (air flow rate in L/min divided by the reactor working volume in liters) hastens the production of MnP with final yield of 63.0 U/L after 3 days. Fourteen repeated batches fermentation were performed without contamination due to low pH (4.5) and aseptic techniques employed.     

Isoflavone transformation during soybean koji preparation and subsequent miso fermentation supplemented with ethanol and NaCl

Soybeans were soaked with water for 4 h, steam-cooked, inoculated with the conidia of Aspergillus oryzae, and incubated for 3 days for koji preparation. The koji was then mixed with water-soaked and steam-cooked soybeans (1:2, w/w), ground into paste, and supplemented with 15% ethanol and 12.5% NaCl or 3% ethanol and 6% NaCl for miso fermentation at 30 degrees C. Daidzin, genistin, daidzein, and genistein contents were extracted from the lyophilized and pulverized soybean powder or from the miso homogenate by a developed one-tube procedure and analyzed with an HPLC. After water soaking, daidzein and genistein contents increased markedly, whereas daidzin and genistin contents decreased. Further increases of daidzein and genistein contents and decreases of daidzin and genistin contents were observed after koji mold growth. During fermentation, fungal and lactic acid bacterial (LAB) growth in the miso products was inhibited, whereas soluble protein contents increased much more rapidly in the low-salt miso products supplemented with 3% ethanol and 6% NaCl than the other products. When the 4- and 8-week-fermented miso products were cooked with tofu for sensory evaluation, flavor ratings of the low-salt products were higher than that of a popular commercial product. In both products, the most daidzins and genistins were hydrolyzed after 4 weeks of fermentation. The hydrolytic enzymes contributing to isoflavone transformation originated from soybeans after water soaking and from koji with mold growth. It was of merit that the low-salt fermented products were fairly acceptable in flavor rating and rich in daidzein and genistein contents after 4 weeks of fermentation.     

秸秆固态发酵酒精过程中湿度变化的研究

研究了在转轴式反应器中以秸秆为原料,接种康氏木霉TR6(Trichoderma koningii)和耐高温酵母CB2(saccharomyces cerevisiae)同步固态发酵酒精的过程中,底物湿度对生物量、纤维素酶活和酒精产量的影响。结果显示：产纤维素酶的最适底物湿度和产酒精的最适底物湿度并不一致;试验研究得到了发酵温度对底物湿度变化的影响最大,通气速率影响次之,菌体呼吸强度的影响最小。     

利用酒糟生物质发酵生产燃料乙醇的试验研究

研究了采用固态发酵工艺利用酒糟生物质生产燃料乙醇的工艺。向酒糟生物质中加入0.05%液化酶，0.06%糖化酶，0.8%纤维素酶，0.4‰TH-AADY，调整酒糟生物质的酸度为3.0，含水率为60%，起始温度为22～24℃，发酵周期为9 d的条件下，燃料乙醇产率可达4.18%。中试结果表明，该工艺可正常生产燃料乙醇，产率为4.03%。本研究可以为酒糟生物质资源的合理利用、消除酒糟对环境的污染、开发可再生新能源提供一条新工艺。     

生物传感器在纤维素乙醇测定中的应用

为探讨生物传感器在纤维素乙醇测定中的应用,采用乙醇生物传感器分析仪对发酵液中的纤维素乙醇含量进行测定,分析其特点、规律。结果：乙醇生物传感分析仪线性关系良好,线性范围为0.2～20.0 mg/100 mL,回归方程为：Y=5.00225X+0.72273,R＝0.99976;对乙醇的检测快速而准确,检测时间为20 s,回收率为99.3%～100.4 %;与气相色谱方法、酒精计法相比较,差异不显著（P>0.05）;专一性强,且仪器重现性和稳定性较好,检测灵敏度高,检测下限为0.2mg/100mL。乙醇生物传感分析仪用于纤维素乙醇检测,具有检测精度高、速度快（20s）、稳定性好、使用成本低等优势,有望代替酒精计、气相色谱仪等,成为检测纤维素乙醇含量的新方法、新手段。     

乙醇水溶液提取玉米胚芽油的工艺优化

为了解决水酶法提取玉米胚芽油生产成本高、提取时间长的缺点,该文采用乙醇水溶液作为提取剂提取玉米胚芽油。通过对粒径、料液比、温度、乙醇体积分数、p H值和时间等条件对油在油相、水相和渣相中分布的研究发现,物料粒径和乙醇体积分数对提高清油得率具有显著(P0.05)的影响,而提取时间对清油得率的影响最小(P0.05)。在单因素试验的基础上通过正交试验,得出乙醇水溶液提取玉米胚芽油的最佳工艺参数为:物料细粉4次(此时粒径为49.18μm)、料液比1∶7 g/m L、温度70℃、乙醇体积分数30%、p H值9.0、提取时间2 h。在该条件下,清油的得率为94.05%±0.32%,水相含油量为3.49%±0.77%,渣相含油量为2.55%±0.82%。分析乙醇水溶液提取的玉米胚芽毛油酸价、过氧化值和含水率等指标发现,该毛油的质量优于国标规定的玉米原油,并且和压榨一级成品油指标接近,只需要经过简单精炼就可以达到食用油要求。研究结果为乙醇水溶液工业化生产玉米胚芽油提供参考。     

玉米秸秆湿氧化预处理同步糖化发酵酒精

为了找到适合的玉米秸秆生产酒精工艺,该文采用碱性湿氧化预处理（195℃,15 min,Na2CO3 2 g/L,O2 1 200 kPa）与同步糖化发酵对玉米秸秆制备酒精进行了研究。结果表明：经过预处理,90%纤维素保留在固体中,回收率为95.87%。固体部分利用纤维素酶处理,在50℃ 24 h酶解率达到了67.6%。底物8%（质量分数）,经过142 h同步糖化发酵,酒精产量达到了理论酒精产量的79.0%。假定五碳糖和六碳糖都能够被利用,相当于1 t玉米秸秆能够产生262.7 kg的酒精。发酵过程中没有明显的抑制作用。该文为玉米秸秆发酵生产酒精提供了试验数据。     

汽爆预处理青玉米秸秆厌氧发酵特性

为了研究青玉米秸秆未汽爆和汽爆预处理后厌氧发酵产沼气特性,该文采用汽爆压力为2.5MPa,保压时间为90s,加入质量分数为30%的沼液,未气爆青玉米秸秆的TS(总固体物)质量分数为6%,汽爆预处理青玉米秸秆厌氧发酵的TS质量分数分别为1%、2%、3%、4%、6%、8%、10%和15%,考察了厌氧发酵过程中pH值和产气量随时间和TS质量分数的变化。结果表明:未汽爆秸秆在TS质量分数为6%时能够顺利厌氧发酵,但汽爆秸秆厌氧发酵液极易酸化,且无法调节,适宜的TS质量分数最大为4%;未汽爆秸秆挥发性固体产气率为214.6mL/g,汽爆秸秆在TS质量分数为3%时产气率最大,为334.8mL/g,比未处理秸秆提高了56%;未汽爆秸秆的产气速率为3.3mL/(g·d),汽爆秸秆产气速率随TS质量分数增大而减小,在TS质量分数为1%时最大,为14.8mL/(g·d)。青玉米秸秆经汽爆预处理后其厌氧发酵产沼气的产气率和产气速率大大提高,可以节约发酵时间,缩短发酵周期,有利于秸秆能源化利用的工业化生产。     

玉米秸秆厌氧产氢工艺参数优化

为解决玉米秸秆结构致密导致秸秆发酵难于直接降解的问题,首先分别采用0.2%、0.4%、0.6%、0.8%的HCl溶液对其进行预处理,以厌氧活性污泥为接种物进行中温(38℃)发酵产氢试验。结果表明,玉米秸秆的累积产氢量和产氢速率随着盐酸质量分数的增大先增加后降低,0.6%HCl处理效果最佳,单位累积产氢量和产氢速率分别为87.90 m L/g和3.05 m L/(g·h)。再以0.6%HCl溶液预处理的玉米秸秆为底物进行发酵产氢的单因素和正交试验,研究了秸秆粒径、底物浓度、初始p H值对玉米秸秆厌氧发酵产氢过程的影响。结果表明:玉米秸秆粒径越小越利于发酵产氢;适度增加底物浓度可增加产氢量;适宜的发酵初始p H值有利于产氢细菌的生长繁殖;得到较佳的工艺参数组合为秸秆粒径150μm、底物浓度15 g/L、初始p H值为7,此时累积产氢量为112.87 m L/g。     

玉米籽皮稀酸水解液脱毒发酵制备丁二酸的可行性

丁二酸是一种重要的碳四平台化合物,利用非粮生物质替代淀粉制备丁二酸可保证粮食安全并降低原料成本。玉米籽皮是一种廉价的非粮生物质,该文采用稀酸水解玉米籽皮制备混合糖液,并对玉米籽皮稀酸水解液的脱毒条件进行了优化,优化结果为：活性炭用量1%（m/V）、pH4.0、作用温度30℃、作用时间30 min。在此工艺条件下,水解液的脱色率为92.27%,糠醛脱除率75%,5-羟甲基糠醛脱除率53%,多酚类化合物脱除率98%,总糖损失低于5%。经过脱毒处理后,产琥珀酸放线杆菌 NJ113均能利用水解液中的葡萄糖、木糖、阿拉伯糖,培养基总糖浓度为50 g/L时,丁二酸分批发酵的质量收率可达0.68 g/g,浓度可达34.2 g/L,生产强度达0.83 g/(L·h),总糖浓度为68.2 g/L时,丁二酸质量收率仍可达0.62 g/g,浓度42.3 g/L,生产强度0.98 g/(L·h)。发酵试验表明脱毒的玉米籽皮稀酸水解液作为碳源厌氧发酵制备丁二酸具有可行性。     

以菊芋粉为原料同步糖化发酵生产燃料乙醇

利用粟酒裂殖酵母（Schizosaccharomyces pombe）能发酵菊芋未水解糖液高产乙醇的特点提出了以菊芋粉为原料,同步糖化发酵生产燃料乙醇的新工艺。在摇瓶中考察了原料预处理方法、原料浓度和初始pH值对乙醇发酵的影响,进而在5 L发酵罐中考察了未调控pH值和恒定pH值与通气情况对乙醇发酵的影响。结果表明：该菌株最适pH值为4.0;100目筛分的菊芋粉发酵效果良好,115℃灭菌处理优于121℃,在此条件下,菊芋粉浓度200 g/L时,乙醇产量达到66.58 g/L,理论转化率为85.88%;发酵液pH值下降对乙醇发酵没有影响,通入适量氧气会导致乙醇产量的下降,这表明粟酒裂殖酵母进行乙醇发酵时不需要供氧;通入氮气保持厌氧环境不能显著提高乙醇产量,不通气进行乙醇发酵也达到高的转化率,因此在工业生产中,不必保持厌氧发酵环境。在此基础上,对菊芋粉补料发酵进行了试验,补料至菊芋粉终浓度为300 g/L,发酵终点乙醇浓度为94.81 g/L,理论转化率为81.54%。这些研究工作,为以菊芋为原料的燃料乙醇工业化生产提供技术依据。     

甜高粱茎秆固态发酵生产燃料乙醇研究

该文通过研究甜高粱茎秆M-81E固态发酵生产燃料乙醇的主要影响因素,确定发酵条件为:耐高温酿酒酵母接种量为3%,发酵初始基质含水率为76%,添加0.25?Cl2,0.25%MgS04·7H2O,40℃发酵24 h,乙醇得率为6.42 g/(100g)甜高粱茎秆,转化率为90.5%,残糖含量低于0.3%;添加10 FPU/g纤维素酶和10 CBU/g β-葡萄糖苷酶,进行同步糖化固态发酵,乙醇得率为7.53 g/(100 g)甜高粱茎秆,与不添加纤维素酶和β-葡萄糖苷酶的相比,乙醇得率提高了14.6%.     

玉米淀粉质原料生料酒精发酵的研究

进行了玉米免蒸煮生料酒精发酵试验,对影响其发酵的主要因素进行正交试验研究,结果表明:玉米生料酒精发酵在发酵剂添加量占原料的0.7%、料水比1∶4、起始pH 5.5、35°C条件下发酵4~5 d,原料淀粉利用率和酒精产率分别可达到81.4%和46.22%。