固定化重组大肠杆菌产1,3-丙二醇发酵条件的研究

利用海藻酸钙将重组大肠杆菌JM109(pHsh-dhaB-dhaG-dhaF-yqhD)固定化,并对影响重组菌固定化细胞发酵的营养因子进行研究。实验结果表明,该重组菌固定化细胞发酵的适宜培养基组成为:甘油80 g/L、酵母膏5.0 g/L、VB120.05 g/L以及KH2PO47.5 g/L;在此培养条件下,1,3-丙二醇产量、转化率及生产能力分别可达61.5 g/L、76.8%和2.57 g(L.h),与游离细胞相比,重组菌固定化细胞对底物甘油和产物1,3-丙二醇的耐受力明显提高,且1,3-丙二醇产量明显提高。     

温度对两种固定化硝化菌硝化反应的影响

通过包埋固定化硝化菌颗粒和生物接触氧化法在不同温度条件下的硝化反应速率测定试验,发现在28℃时两个反应器均达到最大硝化速率,分别为40 mgN/(L.h)和31 mgN/(L.h);温度降至8℃时,硝化速率分别为18 mgN/(L.h)和8 mgN/(L.h),包埋固定化硝化菌在低温条件下显示出明显的优势。温度为20~32℃时,包埋硝化菌处理高氨氮废水很容易形成亚硝酸型硝化。     

聚醚型聚氨酯表面接枝肝素及其表面性质研究

本文研究了通过表面活化点放大来增加聚氨酯（ＰＵ）表面共价结合的肝素量的方法。用化学滴定法测每一步中表面（ＮＣＯ）浓度，用衰减全反射红外光谱，扫描电镜等分析了材料的表面性质，同时测定了肝素浓度。结果证明，与肝素直接接枝到ＰＵ表面相比，本文方法表面接枝肝素量得到较大提高。     

Sodium Lactate/Sodium Chloride Effects on Aerobic Plate Counts and Color of Aerobically Packaged Ground Pork

Ground pork (15% fat) was formulated to contain 0% to 3.0% sodium chloride and/or 0% to 3.0% sodium lactate (SL) resulting in 28 treatment combinations. Five replications consisted of two with low initial microbial loads (< 10³ CFU/g) and three with high initial loads (> 10⁵ CFU/ g). Ground pork (454g) was overwrapped in PVC and stored (4°C) aerobically for 21 d. A significant salt × SL interaction existed for redness of samples with low initial aerobic plate count (APC). Red color was best preserved by 2.0% or 3.0% SL. Initial pH values of low and high initial APC samples were similar. Initial product pH was best maintained by higher SL levels in low initial load samples and by higher sodium chloride levels in high initial load samples. Samples containing 3.0% SL had the lowest APC regardless of salt level.     

Phenol degradation in a fixed‐bed bioreactor using micro‐cellular polymer‐immobilized Pseudomonas syringae

Highly porous (85% void volume) polymer beads with interconnecting micro‐pores were prepared for the immobilization of Pseudomonas syringae for the degradation of phenol in a fixed‐bed column bioreactor. The internal architecture of this support material (also known as PolyHIPE Polymer) could be controlled through processing before the polymerization stage. The transient and steady state phenol utilization rates were measured as a function of substrate solution flow rate and initial substrate concentration. The spatial concentration of the bacteria on the micro‐porous support particles as well as within them was studied using scanning electron microscopy at various time intervals during the continuous operation of the bioreactor. It was found that although bacterial penetration into the porous support was present after 20 days, bacterial viability however, was compromised after 120 days as a result of the formation of a biofilm on the support particles. The steady state phenol utilization at an initial phenol concentration of 200 mg cm^?3 was 100% provided that the flow rate was less than 7 cm³ min^?1. Substrate inhibition at a constant flow rate of 4.5 cm³ min^?1 was found to begin at 720 mg dm^?3. The critical dilution rate for bacteria washout was high as a result of the highly hydrophobic nature of the support and the reduction of pore interconnect size due to bacterial growth within the pores in the vicinity of the surface of the support. Copyright © 2004 Society of Chemical Industry     

Investigation of biofilm growth and attrition in a three‐phase airlift bioreactor using 35SO42− as a radiolabelled tracer

The growth and biomass loss pattern for immobilized cells growing on diatomaceous earth particles in a three‐phase airlift bioreactor (TPALB) is studied using ³⁵S as a radiolabelled tracer. A monoculture of Beneckea natriegens was grown immobilized on support particles in a 3 L TPALB. Sterile conditions were maintained during the experiments, and n‐propanol was used as the sole carbon source. After the system reached steady state, the unlabelled sulfate (SO₄^2?) in the feed tank was substituted by a radioactive grade (³⁵SO₄^2?), and the assimilation of ³⁵S in the immobilized and in the suspended cells was monitored. The results indicated that the growth rate of immobilized biomass was not uniform throughout the biofilm. More specifically, it was concluded that cells growing closer to the external biofilm layer exhibit a higher growth rate, and that biomass loss from the biofilm was through attrition at the outer biofilm surface rather than by sloughing off of whole sections of biofilm. Copyright © 2006 Society of Chemical Industry     

吉林油田微生物提高原油采收率现场试验研究

本文介绍了吉林油田现场试验研究的历程.建立了采用DNA鉴定用于微生物提高原油采收率的微生物的新技术.筛选出了用于现场试验的有用的微生物.通过就地注入糖蜜微生物单井吞吐与驱替试验,考察了油藏中被激活细菌的行为,原油收率,含水率及原油的粘度.代谢生物多糖的CJF-002用于现场试验中的微生物中最好的菌种.因为它可以使用糖蜜作为营养源,产生少量的CO2及大量的水不溶性的生物聚合物.它在油藏的代谢行为表明CJF-002具有微生物提高原油采收率良好潜力.     

Synthesis of docosahexaenoic acid-rich triglyceride with immobilizedChromobacterium viscosum lipase

Docosahexaenoic acid (DHA) in the free fatty acid (FFA) derived from enzymically hydrolyzed tuna oil was concentrated by partial titration and precipitation of other FFA as sodium salts with acetone. A triglyceride containing up to 46.2% DHA was synthesized from the DHA-rich glyceride mixture and FFA by use of an immobilizedChromobacterium viscosum lipase.     

包埋固定硝化菌的亚硝化特性研究和系统调控

在使用包埋固定化硝化菌的流化床反应器中改变系统的运行参数,用模拟高浓度NH3-N废水实现从常规硝化为主到亚硝酸型硝化为主的转变。驯化完成、恢复溶解氧到3~4 mg/L后,仍然能达到高度的亚硝酸型硝化。通过间歇式实验得出亚硝酸盐的积累率随反应时间的变化规律,以此为参考调控连续进出水情况下的水力停留时间(HRT),从而达到和保持最好的亚硝酸型硝化效果。