Scale-up of fermentation and purification of recombinant allophycocyanin over-expressed in Escherichia coli

Phycobiliprotein is a photosynthetic antenna pigment found in cyanobacteria, rhodophytes, cryptophytes and certain dinoflagellates, which has been found to have anti-oxidative and anti-tumour activities. In this paper, a recombinant allophycocyanin (rAPC) had been expressed in Escherichia coli for anti-tumour effect. E. coli cells were cultured using glucose fed-batch method to achieve high cell densities. The biomass of rAPC was up to 3.52 g/L broth. The rAPC was purified from soluble E. coli cell lysate employing hydrophobic interaction chromatographic (HIC) method developed at the bench scale using 20 mL column. The process was performed at the pilot scale using 500 mL column for evaluation of scale-up. An amylose affinity column was used to improve the purity of final product in pilot scale purification. The purification process resulted in greater than 98% pure product and yielded up to 2.0 g/kg wet cells at the bench scale and 1.2 g/kg wet cells at the pilot scale. Peptide mapping was used to prove the identity of rAPC purified from bench scale and pilot scale process. Purified rAPC at the pilot scale was found to have remarkable inhibition on S-180 carcinoma in mice. (c) 2005 Elsevier Ltd. All rights reserved.

污泥处理经济评价和污泥堆肥中氧气监测与动态分析

With the continually increase both in the amount of wastewater disposal and in the treatment rate, more and more sewage sludge has been produced. An economic estimate was taken on the different sewage sludge disposal and treatment technologies, and led to the conclusion that compost is an effective way to make sewage sludge harmless, stable and resourceable. Normally, there are several ways to treat sewage sludge, such as landfill, compost, incineration and so on. These technologies will cost 300-1000 Y per ton of sludge. Among those ways, landfill is the cheapest one and operates easily, however, it just postpones the pollution instead of eventually eliminating the pollution; The amount of the sludge will reduce dramatically after incineration, while incineration will take a very high investment in the beginning, at the same time, it's very hard to maintain running; Sewage sludge will be resourceful after composting treantment, thus makes up the treatment cost, makes composting is the most economical way. Compost production is safe when correctly used, compost is a important way to treat sewage sludge. Oxygen is an important control factor in aerobic composting that has great effects on temperature and microorganisms. The gas gathering and transfering system of an online oxygen monitoring system for composting were bettermented to prolong the monitoring system's running period. The oxygen concentration changes in various aerobic composting stage were studied, and conclusions came to that oxygen concentration changes much faster in the oxygen concentration increasing stage than that in the declining stage; the better the aerobic condition is, the sooner the monitoring system starts to work. The minimal oxygen concentration during a ventilation cycle often falls at the beginning, then ascends in the composting period; at the same time, oxygen concentration changes fast in the early composting stage(temperature increasing stage), much slower in the middle stage(continouns thermophilic stage),and seldom changes in the late composting stage(temperature declining stage). With the help of the oxygen realtime-online monitoring system, oxygen concentrations was measured. During the composting period, water contents was analyzed after sampled. It's found that water contents (WC) and Oxygen concentration can both influence the composting process, and the control rule varies in the various composting stages. Essentially, the rule that water and oxygen control the composting process comes from water counterchecks the oxygen transferring to the composting substrate. The most influential factor to the WC and to the oxygen is the components in the composting pile. In the temperature increasing stage, seldom microorganisms exist in the composting pile with low activity, thus oxygen can meet with microorganisms' need, and WC is the dominant factor. In the high temperature (continouns thermophilic) stage, composting process is controlled by WC and oxygen, essentially by WC, at the same time, their influence somehow is not remarkable. In the temperature declining stage, WC and oxygen influence the composting process little. It's also found that the composting process will differ even if under the same components, thus to equably mix the components can avoid WC focusing in some place and let the composting pile to be aerobic. In one sentence, aerobic state is the most important factor in the composting process, suitable bulking material will be useful to the composting control.