三菌复合发酵提高厨余真蛋白含量的研究

为改善厨余发酵的品质,增加发酵后产品蛋白含量。采用三菌复合对厨余进行发酵,探讨了三菌复合的比例、接种量、发酵时间、初始pH值对发酵效果的影响,采用L9(34)正交实验对发酵条件进行优化,并对实验菌Lc和Ydy进行16S rRNA及18S rRNA分子鉴定。结果表明,最佳发酵条件为:菌剂配比(Lc∶Ydy∶S1)为3∶2∶1,接种量为0.15%,初始pH值为5.0,发酵时间为48 h。扩大实验结果表明,在最优发酵条件下,厨余经发酵后品质得到改善,真蛋白含量由发酵前的15.42%上升到发酵后的22.47%,增加率为45.80%;发酵后大肠菌群下降到30 cfu/g以下;乳酸菌及酵母菌数量分别为1.5×109 cfu/g和6.6×108 cfu/g。分子测序及鉴定结果表明,Lc为乳酸乳球菌,Ydy为热带假丝酵母菌。     

微生物酶促高效提制废次烟草中烟碱的研究

采用酶促反应利用微生物发酵处理废次烟叶提取烟碱,对比发酵及微波协助等不同方式,利用分光光度法测定发酵体系中烟碱溶出含量,优选出发酵菌种,并探讨接种量和培养基质及不同工艺参数等对烟碱含量的影响。实验结果表明:选用白腐真菌和管囊酵母(1∶1)在微波协助处理下,当烟叶与水的重量比为3∶20,豆粕与烟叶重量百分比为15%,接种量40%,pH=6,30℃发酵48 h,能得到烟草中烟碱溶出浓度为3.291 g/L,为有效实现废次烟草减量化排放与资源化利用结合奠定基础。     

蛋白多肽对强酸化土壤的改良效应

以强酸化土壤(pH为4.30)为研究对象,以蛋白多肽为新型土壤改良剂,将传统施加生石灰的酸化土壤治理技术和施加复混肥的常规种植技术为对照,研究蛋白多肽对强酸化土壤的改良效应。结果表明:土培实验中的蛋白多肽与生石灰对强酸化土壤均有碱化效应,将土壤pH分别提高了0.23和0.30 (120 d稳定值),而复混肥碱化程度较低(提高0.02);同时,蛋白多肽组与生石灰组土壤交换性酸含量比复混肥组(35.93 mmol·kg~(-1))分别降低了12.56 mmol·kg~(-1)和18.68 mmol·kg~(-1),盐基饱和度分别比复混肥组(67.30%)高7.01%和9.85%;蛋白多肽组土壤有机质含量(19.96 g·kg~(-1))变化尤为明显,并且,显著高于复混肥组(8.58 g·kg~(-1))和生石灰组(12.23 g·kg~(-1))。蛋白多肽与生石灰均能提高强酸化土壤pH,但未能一次性达到6.5以上的中性程度。基于此,以结球甘蓝为供试植物,研究此背景下的种植情况。结果显示,蛋白多肽可在偏低pH条件下种植出高产的结球甘蓝,比其他组合效果明显,其平均生物量(371.78 g)比复混肥组和生石灰组分别高9.54倍和1.90倍。蛋白多肽具有改良强酸化土壤的潜力,并能达到改良与种植同步化(蛋白多肽施加后直接种植作物幼苗)。研究结果可为强酸化土壤的改良与种植提供参考。     

林可霉素菌(Streptomyces lincolnensis)利用吡唑酮废水的研究

采用被吡唑酮废液驯化、分离、筛选后的林可霉素菌,并对其在摇瓶上利用吡唑酮废液中的硫酸铵发酵(7 d)生产林可霉素进行了研究。实验结果表明,废液加入培养基体积比都为1∶10,实验1中菌丝代谢和对照比正常,其中还原糖利用最快,在发酵后期为0.24 mg/L,林可霉素起步效价最低为2 100 IU/mL,与对照相比最后发酵效价降低了70 IU/mL;实验2发酵过程pH值偏低,全程为5.86～6.50,氨基氮代谢缓慢为40 mg/100 mL,最后林可霉素效价最低为4 480 IU/mL;实验3中废液在发酵进入48 h中后期的时候补入能促进菌丝体分泌,最后林可霉素为5 180 IU/mL,比对照发酵水平高出8.82%。可见实验3的实验设计有利于林可霉素菌利用吡唑酮废液生产林可霉素,为废物循环利用、变废为宝的可行性作了有意义尝试。     

稻秸、餐厨垃圾及人粪尿混合厌氧发酵

采用批次及批次与半连续耦合的发酵方法,35℃条件下,研究了稻秸与餐厨垃圾、人粪尿混合物(简称生活污水,下文同)的不同混合比例以及生活污水不同负荷对稻秸产沼气性能及污水中粪大肠菌群去除率的影响。结果表明:在发酵总固体浓度(TS)为16%条件下,稻秸与生活污水混合比例为1∶1.72(W/W)时,稻秸TS产气量达到377 mL/g,比稻秸与生活污水比为1∶3.44的处理高7.71%,比单一稻秸高24.42%;在稻秸TS浓度为10%条件下,生活污水有机负荷(OLR)从0.5 g COD/(L.d)逐步提高到4.0 g COD/(L.d),其厌氧发酵系统运行正常,与单一稻秸发酵相比,容积产气效率提高,且沼气中甲烷含量提高近20%,与单一生活污水厌氧发酵相比,生活污水COD去除率基本一致,均超过80%,但是随着污水有机负荷的增加,粪大肠菌群去除率由99.4%下降到了86.0%,出水中粪大肠菌群未达到国家允许的1×104个/mL排放标准。     

两步法处理含油污水的研究

利用微生物法,分絮凝和降解两步处理含油污水。第1步优化了高效产絮凝剂菌絮凝条件。结果表明,培养40h的产絮凝剂菌液具有最佳的絮凝活性,菌液质量浓度为0.25g/L,投加量为6 mL/L,pH为5~14,絮凝助剂为CaCl2时絮凝效果最佳。第2步优化了高效降解菌的降解条件。结果表明,以原油为碳源,鱼粉为氮源,碳氮比(质量比)20∶1,初始pH=8,含油率9.0%,含水率60%时,降解菌降解率最高。在以上优化条件下,含油污水的原油去除率可达77.4%。因此,全程利用微生物,分絮凝富集、固体培养两步无害高效处理含油污水是可行的。     

林可霉素菌（Streptomyces lincolnensis）利用吡唑酮废水的研究

采用被吡唑酮废液驯化、分离、筛选后的林可霉素菌,并对其在摇瓶上利用吡唑酮废液中的硫酸铵发酵（7 d）生产林可霉素进行了研究。实验结果表明,废液加入培养基体积比都为1∶10,实验1中菌丝代谢和对照比正常,其中还原糖利用最快,在发酵后期为0.24 mg/L,林可霉素起步效价最低为2 100 IU/mL,与对照相比最后发酵效价降低了70 IU/mL;实验2发酵过程pH值偏低,全程为5.86～6.50,氨基氮代谢缓慢为40 mg/100 mL,最后林可霉素效价最低为4 480 IU/mL;实验3中废液在发酵进入48 h中后期的时候补入能促进菌丝体分泌,最后林可霉素为5 180 IU/mL,比对照发酵水平高出8.82%。可见实验3的实验设计有利于林可霉素菌利用吡唑酮废液生产林可霉素,为废物循环利用、变废为宝的可行性作了有意义尝试。     

汽爆秸秆高温固态发酵沼气的研究

沼气液态深层发酵及秸秆的物理、化学和生物预处理方式存在效率低、污染重等问题。为了解决这些问题,对蒸汽爆破预处理方式以及固态发酵在玉米秸秆沼气化中的应用进行了研究。秸秆经过蒸汽爆破预处理后,在50℃的高温条件下进行固态发酵沼气,甲烷产量达到138.2 mL/g TS。通过单因素实验优化,确定最佳发酵条件为：固液比1∶7,初始pH值7.5,接种量35%,NH₄HCO₃添加量0.04 g/g干汽爆秸秆,纤维素酶用量30 IU/g干汽爆秸秆,发酵温度50℃。在上述实验条件下,汽爆秸秆的甲烷产量提高至153.0 mL/g TS,是未汽爆秸秆的2.9倍。发酵后秸秆纤维素和半纤维素的降解率分别为59.86%和67.22%。因此,蒸汽爆破预处理有助于提高秸秆的产气量和降解率。高温固态发酵不仅可以缩短发酵延迟期,提高产气效率,而且发酵结束后不会产生大量废液,对环境友好。     

污泥水解蛋白液对食用菌生长的影响研究

将污泥(食品工厂污泥)经过酸碱水解制备水解蛋白液(肽类和氨基酸复合物,属于微生物蛋白)、并与豆粕(植物蛋白)、屠宰厂动物羽毛(动物蛋白)水解蛋白液、以及常规食用菌氮源麸皮、大米制糖厂米渣作为平菇栽培氮源或营养添加剂,测试对平菇的菌丝生长、产量和生物转化率的影响。结果表明,几种水解蛋白液对平菇的菌丝生长、产量、生物转化率影响明显,污泥水解蛋白液对菌丝的生长效果最好,其余2种水解蛋白液也有促进作用。添加污泥水解蛋白液最高产量可达806 g/袋,添加豆粕水解蛋白液的最高产量为532 g/袋,添加屠宰厂动物羽毛水解蛋白液的产最高量为525 g/袋;对照为480 g/袋(常规棉籽壳)。生物转化率分别为161.2%、106.4%和105.0%,而对照生物转化率为96%;增产率分别为67.92%、10.83%和9.38%。因此,污泥、豆粕、屠宰厂动物羽毛蛋白水解液可提高平菇产量,该研究也为污泥资源化利用建立了基础。     

应用酵母菌处理木薯酒精废液的试验研究

应用酵母菌对木薯酒精废液进行了小型批量的处理试验研究.结果表明,该菌种对于高浓度有机废水具有很强的适应能力,能迅速形成优势菌群,分解有机物.在进水pH 5.0～5.5、温度30℃、曝气时间72 h、接种量1‰(v/v,活菌数为4.1×106个/mL)、溶解氧2～3 mg/L、BOD5∶N∶P为400∶2∶1条件下,COD和BOD5去除率可分别达85%和92%.该技术操作简单,可作为木薯酒精废液的一级生物处理,并可回收利用酵母蛋白.     

Solubilization of blood meal to be used as a liquid fertilizer

The solubilization of blood meal by means of the microwave-hydrogen peroxide enhanced advanced-oxidation process (MW/H(2)O(2)-AOP) was studied. It was found that over the treatment temperature range of 60 to 120 degrees C, solids particle reduction, ammonia and orthophosphate production could be achieved by this process. Large protein molecules were broken down into intermediate compounds with low molecule weights, ammonia and nitrate. Intermediate compounds, such as peptides and amino acids, can also be easily converted to nitrogenous nutrients for plant growth by bacteria. Soluble nitrogen content increased with an increase in microwave heating temperature when acid was added; significant amounts of ammonia were obtained at higher temperatures. Nitrate decreased in concentration with an increase of treatment temperature. Orthophosphate concentrations increased after the advanced-oxidation process (AOP) treatments, with and without acid addition; but were more pronounced with acid addition. Maximum solubility of chemical oxygen demand (COD) occurred at 80 degrees C. Without the addition of acid, soluble COD decreased due to protein denaturation and coagulation out of the solution.     

Chemical evidence and risks associated with soybean and rapeseed meal fermentation

The storage and transport of cereals and foodstuffs present recurrent problems. They may be attacked by insects or, under certain conditions, they may undergo spontaneous fermentation. Insect attack is normally avoided by fumigants, while fermentation, which depends on parameters such as temperature and humidity, is more difficult to stop and can produce chemical compounds which irremediably modify the nutritional and compositional properties of foodstuff. This paper describes the main chemical compounds produced by fermentation and self-ignition of soybean and rapeseed meal. Reported cases occurred in a storage site and during transport by ship, respectively.     

Dioxin production during the thermal treatment of meat and bone meal residues

Safe animal by-product disposal is a priority target as a result of the Bovine Spongiform Encephalopathy crisis in the European beef industry. One such disposal option is the incineration of by-product material such as meat and bone meal residues (MBM) for the purpose of energy recovery. Although currently applied, the thermal decomposition of MBM wastes has not been scientifically studied until now. A series of experiments has been performed to study the thermal behavior of MBM both in inert (N2) and reactive atmosphere (air), both by thermogravimetry and in a horizontal laboratory furnace. As a general trend, MBM gives low PCDD/F values, compared with incineration of other wastes. Maximum yield of pollutants is observed at a nominal temperature between 700 and 800 degrees C.     

Oxalic acid activated bone meal for immobilization of Pb and Cd contaminated soils

Environmental Science and Pollution Research - Bone meal (BM) is a cost-effective and low-carbon material to remediate heavy metal contaminated soils. Moreover, its immobilization efficiency for...     

Hazardous air pollutants formation from reactions of raw meal organics in cement kilns

Thermally induced chlorination, condensation, and formation reactions of raw meal organic surrogates were investigated on different types of surfaces. The System for Thermal Diagnostic Studies provided a powerful tool to study these reactions under defined reaction conditions, which were related to typical conditions in the preheater zone of cement kiln. Experiments were conducted with benzene and benzene/myristic acid (C6H6/C13H27COOH) mixtures in a quartz reactor containing different chlorinating catalysts/reagents over a temperature range of 300-500 degrees C. Reaction products were trapped in-line and analyzed by GC-MS. A mixture of chlorides of calcium, potassium, aluminium and iron was highly effective for chlorination/condensation reactions of benzene and benzene/myristic acid mix at temperatures above 300 degrees C. The same behavior was observed only when calcium chloride and potassium chloride were used as chlorinating catalyst/reagent. This result showed that transition metal chlorides like FeCl3 are not necessary for chlorination/condensation of organics under post-combustion conditions. Methylene chloride was the major chlorinated product followed by chloroform and various other C1, C2 and C6 chlorinated products. Yields of chlorinated aliphatics were highest at 400 degrees C for both benzene and benzene/myristic acid mix. C6 products were mainly mono- to hexa-chlorinated benzenes with trace amounts of chlorinated phenols. The major chlorinated products observed in this study (i.e., methylene chloride, chloroform, chloroethanes and monochlorobenzene) were also present as major chlorinated hydrocarbons in the cement kiln field emission data.     

可降解餐盒去除地下水硝酸盐的砂槽模拟实验研究

采用室内砂槽实验装置,研究了以可降解餐盒(BMB)为反硝化碳源的生物反应器对于模拟污水中硝酸盐的去除效果及其影响因素。结果表明,以BMB为反硝化碳源的反应器启动时间短。当进水硝酸盐浓度为50 mg/L,水温为25℃,水力停留时间为1.15 d时,硝酸盐的去除率可达92.6%以上,实验过程中出现亚硝酸盐积累,出水TOC浓度上升,但反应稳定后亚硝酸盐浓度均低于0.1 mg/L,且TOC浓度有下降趋势;水力停留时间减小或者进水硝酸盐浓度增加均能使得脱氮效率降低,但当水力停留时间在0.57~1.15 d,进水硝酸盐浓度在50~80 mg/L范围变化时,反应器硝酸盐去除效率仍能达到80%以上;温度对反硝化作用影响较大,当温度为(20±1)℃时,硝酸盐的去除效率仅为62.0%、74.4%和97.5%。     

Industrial processing versus home cooking: an environmental comparison between three ways to prepare a meal

Today there is a strong trend in Sweden for industrially processed meals to replace homemade meals. In the public debate this is often claimed to increase the environmental impact from foods. In the study presented in this article, we used life-cycle assessment to quantify the environmental impact of three meals: homemade, semiprepared, and ready-to-eat. The differences in environmental impact between the meals were small; the ready-to-eat meal used the most energy, whereas the homemade meal had higher emissions causing eutrophication and global warming. The dominating contributor to the environmental impact was agriculture, accounting for 30%, of the impact related to energy and 95% of that related to eutrophication. Industry, packaging, and consumer home transport and food preparation also contributed significantly. Important factors were raw material use, energy efficiency in industry and households, packaging, and residue treatment. To decrease the overall environmental impact of food consumption, improvements in agriculture are very important, together with raw-material use within industry and households.     

Effect of bone meal (calcium phosphate) amendments on metal release from contaminated soils--a leaching column study

Metal-contaminated soil may be remediated in situ by the formation of highly insoluble metal phosphates if an appropriate phosphorus (P) source can be found. Leaching column experiments have been carried out to assess the suitability of bone meal as such a source. Bone meal additions reduced metal release from a contaminated soil, increased soil and leachate pH and decreased soil leachate toxicity. Minimal P leaching occurred from the soil. The data are consistent with a proton consuming bone meal (calcium phosphate) dissolution reaction followed by the formation of metal phosphates. Although, no metal phosphates were observed to form using X-ray diffraction of scanning electron microscopy this could be due to their low concentration. Relatively low (1:50 bone meal:soil) concentrations of fine (90-500 microns) bone meal would appear to be an effective treatment for metal-contaminated soils.     

Tolerance of S. cerevisiae and Z. mobilis to inhibitors produced during dilute acid hydrolysis of soybean meal

The objective of this research was to determine the minimum inhibitory concentration of 5-hydroxymethyl furfural, furfural, and acetic acid on Saccharomyces cerevisiae (NRRL Y-2233) and Zymomonas mobilis subspecies mobilis (NRRL B-4286) in both detoxified hydrolyzed soybean meal and synthetic YM broth spiked with the three compounds. Soybean meal was hydrolyzed with dilute sulfuric acid (0.0, 0.5, 1.25, and 2.0% wt v^?1) at three temperatures (105, 120, and 135°C) and three durations (15, 30, and 45 min) followed by detoxification with activated carbon. Of all the combinations, only the treatments obtained at 135°C, 2.0% H₂SO₄, and 45 min and the one at 135°C, 1.25% H₂SO₄, and 45 min showed inhibition in the growth of the tested microorganisms. Spiked YM broths showed inhibition for the highest levels of inhibitors, either applied individually or in combination.     

Use of bone meal amendments to immobilise Pb, Zn and Cd in soil: A leaching column study

The aim of this study is to test the stabilisation of metals in contaminated soils via the formation of low-solubility metal phosphates. Bone apatite, in the form of commercially available bone meal, was tested as a phosphate source on a mine waste contaminated made-ground with high levels of Pb, Zn and Cd. Triplicate leaching columns were set up at bone meal to soil ratios of 1:25 and 1:10, in addition to unamended controls, and were run for 18 months. The columns were irrigated daily with a synthetic rain solution at pH of 2, 3, and 4.4. After 100 days, the leachate Pb, Zn and Cd concentrations of all amended columns were significantly reduced. For 1:10 treatments, release of these metals was suppressed throughout the trial. For 1:25 treatments, Zn and Cd concentrations in the leachates began to increase after 300 days. DTPA and water extractions showed that Pb and Cd were more strongly held in the amended soils. This study concludes that the complexity of soil processes and the small quantities of metals sequestered precluded determination of a metal immobilisation mechanism.