Ethanol production from alkali-pretreated oil palm empty fruit bunch by simultaneous saccharification and fermentation with mucor indicus

Oil palm empty fruit bunch (OPEFB) is a potential raw material for production of lignocellulosic bioethanol. The OPEFB was pretreated with 8% sodium hydroxide (NaOH) solution at 100°C for 10 to 90 min. Enzymatic digestion was carried out using cellulase and β-glucosidase at 45°C for 24 h. It was then inoculated with Mucor indicus spores suspension and fermented under anaerobic conditions at 37°C for 96 h. Sodium hydroxide pretreatment effectively removed 51–57% of lignin in the OPEFB and also its hemicellulose (40–84%). The highest glucan digestibility (0.75 g/g theoretical glucose) was achieved in 40-min NaOH pretreatment. Fermentation by M. indicus resulted in 68.4% of the theoretical ethanol yield, while glycerol (16.2–83.2 mg/g), succinic acid (0–0.4 mg/g), and acetic acid (0–0.9 mg/g) were its by-products. According to these results, 11.75 million tons of dry OPEFB in Indonesia can be converted into 1.5 billion liters of ethanol per year.     

模拟氯化钠盐渣的高温处理

采用高温处理法对模拟氯化钠盐渣（简称盐渣）进行处理,研究了加热过程中气体有机物产生量随加热时间的变化规律以及加热温度对气体有机物产生量的影响,并分析了盐渣的高温处理效果。实验结果表明：含苯盐渣、含异丁醇盐渣、含氯苯盐渣、含二甲苯盐渣和混合盐渣在高于盐渣中所含有机物沸点30 ℃的条件下加热120 min,盐渣中的有机物去除率均大于99.99%;混合盐渣的加热温度越高,气体有机物的产生速率越快,相同时间内有机物的去除率也越大;盐渣中有机物的气化分离可分为3个阶段,初始阶段有机物气化速率较小,中间阶段气体有机物产生量迅速增加,最后阶段大部分有机物从盐渣中气化分离;盐渣中的有机物在高温气化时,会发生一定的化学反应,有微量的新物质生成。     

海藻酸钠-聚乙烯醇-聚乙二醇复合膜的制备及其对Cu2+的吸附

采用聚乙烯醇（PVA）、聚乙二醇（PEG）对海藻酸钠（SA）进行改性,制备了一种新型高效SA-PVA-PEG复合膜。研究了该复合膜对Cu²⁺的吸附效果。用IR和SEM等手段对复合膜进行了表征。表征结果显示,复合膜内部存在孔状结构,有利于吸附Cu²⁺。实验结果表明：在初始Cu²⁺质量浓度50 mg/L、复合膜加入量1 g/L、废水pH=5、吸附温度30 ℃、吸附时间60 min的最佳条件下,吸附率最高可达90.1%,吸附量达25.3 mg/g;复合膜吸附Cu²⁺的动力学过程可用二级动力学方程和Elovice方程进行拟合,吸附过程符合Langmuir单层吸附理论。采用浓度为1 mol/L的HCl溶液对吸附后的复合膜进行解吸,当解吸时间为2 min时,解吸率可达80.0%。     

含氟离子和氯离子酸性废水处理技术

本实验研究了石灰乳和铝酸钠处理废水中的氟离子和氯离子的效果。通过正交实验得出:影响除氟离子效果因素的主次顺序为:pH值>氟离子浓度>反应时间;影响除氯离子效果因素的主次顺序为:氯离子浓度>铝酸钠与氯离子的质量浓度比>反应时间。通过单因素实验得出:在pH=9、反应时间为5 min的条件下,废水中氟离子含量可由370.37mg/L降低到2 mg/L以下,去除率可达99.45%;在铝酸钠与氯离子的质量浓度比为1∶10,反应时间为5 min的条件下,废水中氯离子含量可由503.4 mg/L降低到201 mg/L以下,去除率可达60%。     

NaClO2/NaClO复合吸收液同时脱硫脱硝

针对NaClO2氧化吸收法脱硫脱硝成本过高,难以实现工业化的现状,提出了以NaClO2/NaClO为复合吸收剂的同时脱硫脱硝新方法,比单独NaClO2方法效率高,成本低。考虑实际工况条件,给定SO2与NO的初始浓度分别为2 850 mg/m3和670 mg/m3。结果表明,吸收液初始pH为6.0,液气比L/G为20 L/m3,反应温度为55℃时,平均脱硫脱硝效率分别可达99.8%和94.0%。在此基础上对反应机理进行了分析,总结出实验反应主反应方程式。该方法设备简约,操作简单,容易实现全自动控制,综合成本可以接受,比较适合中小型燃煤锅炉的烟气污染治理。     

硫化物沉淀法处理含铅废水

采用硫化物沉淀化处理含铅废水,考察了Na2S投加量、反应初始pH等操作条件对铅离子去除效果的影响,以及硫化铅沉淀反应过程的动力学特征,并采用激光粒度分析仪对反应生成的硫化铅沉淀的粒径分布进行了测定。实验结果表明,S2-与废水中Pb2+之间的沉淀反应能较好地符合一级反应动力学特征;Na2S与Pb2+的最佳物质的量之比为3;最佳的反应初始pH为6～9。在最佳操作条件下,Pb2+的平均去除率为99.60%,反应出水中Pb2+平均浓度为0.13 mg/L,低于污水综合排放标准(GB8978-1996)中铅的排放浓度限值。反应生成的硫化铅沉淀的平均粒径为2.62μm,具有较好的沉淀性能,能够通过沉淀的方式与废水分离。     

两性高分子重金属螯合絮凝剂的合成及其对Cu(Ⅱ)的去除性能

合成了一种新型两性高分子重金属螯合絮凝剂聚(氯化二烯丙基甲基羟丙多胺基铵)基二硫代甲酸钠(PDAMHACDTC),采用元素分析、红外光谱、紫外光谱和核磁共振谱对其结构进行表征。考察了其对含Cu2+废水的处理效果,以及絮体的沉降速度;测定了微絮体的ζ电位,采用扫描电镜考察了絮体的形貌。结果表明,当PDAMHACDTC中—CSS-与Cu2+的物质的量之比接近2∶1,对Cu2+的去除率大于99.7%,残余Cu2+浓度远低于国家污水综合排放一级标准0.5 mg/L;在相同—CSS-投加量时,形成的微絮体的ζ电位和絮体沉降速度分别比以聚(二甲基二烯丙基氯化铵-丙烯酰胺)为母体合成的两性高分子螯合絮凝剂(ACPF)形成絮体大,说明PDAMHACDTC比ACPF更利于中和絮体上过剩负电荷,促进絮体的形成和生长。     

催化湿式过氧化法处理蒽醌-2-磺酸钠废水

以过渡金属Cu为主活性组分,通过加入第2活性组分Mn和稀土元素Ce,研制出适用于催化湿式过氧化法(CWPO)处理含高浓度蒽醌-2-磺酸钠有机废水的复合催化剂。考察了活性组分配比对催化剂的催化活性和稳定性的影响,并利用SEM和XRD表征手段,研究了掺杂Ce对催化剂表面微观结构的影响。结果表明,当Cu、Mn和Ce的质量比为-时,催化剂的催化性能最佳,在100 min内,废水COD的去除率能达到95.3%;掺杂Ce能有效提高活性组分在催化剂表面的分散程度从而改善催化剂的催化活性,并能有效抑制Cu的溶出。通过LC-MS分析该催化剂催化氧化蒽醌-2-磺酸钠降解过程中的代谢产物,推断出了催化氧化降解蒽醌-2-磺酸钠的途径。     

Extracellular antimutagenic activities of selected probiotic Bifidobacterium and Lactobacillus spp. as a function of growth phase

The capabilities of selected strains from genera Lactobacillus and Bifidobacterium to produce extracellular bioactive compounds with antimutagenic properties against benzo[a]pyrene (BaP) and sodium azide (SA) were tested as a function of growth phase. The bacterial supernatants from exponential and stationary phases were characterized with different patterns of antimutagenic activity against the two mutagens. All lactobacilli exhibited either no effect or low antimutagenicity against BaP during exponential growth. Higher antimutagenic activities of lactobacilli supernatants were observed in the stationary phase against SA as well. An exception was Lactobacillus sakei 23K which expressed a relatively low percent of inhibition of mutagenesis (PI = 28.14 ± 7.41) in the exponential phase and no antimutagenic activity in the stationary phase. Of the bifidobacteria, only Bifidobacterium adoleascentis ATCC 15703 exhibited higher antimutagenecity against BaP in the exponential phase. The same bacterial supernatants however, did not possess any antimutagenicity against SA in either the exponential or stationary phases. B. bifidum ATCC 11863 did not express any significant differences in its activity against either BaP or SA in the exponential or stationary phases. Only B. breve ATCC 15700 expressed a high antimutagenic effect against SA in the stationary phase but exhibited no effect during exponential growth. Overall, bacterial antimutagenic responses were associated with growth phase and type of mutagen.     

Listeria monocytogenes batch culture growth response to metabolic inhibitors

In certain environments nutrient and energy sources available to microorganisms can be limited. Foodborne pathogens must efficiently adapt in order to be successfully transmitted through the food chain to their hosts. For the intracellular foodborne pathogen Listeria monocytogenes, little is known regarding its response to nutrient/energy-limiting conditions. The alternative stress responsive sigma factor σ^B has been reported to contribute to survival under specific stresses. Therefore, the effects of several metabolic inhibitors on growth of L. monocytogenes wild-type and a ΔsigB mutant were examined. In the absence of inhibitors, both strains reached stationary phase after 18 h at 23°C and 10 h at 37°C. All of the metabolic inhibitors slowed growth of either strain, with few differences observed among the different inhibitors.