化学化工专业英语试题_化学工程与工艺专业英语阅读教程_化学工程与工艺考教师(12)

TheabilityofpenicillintopreventtheonsetofsepticemiainbattlewoundsduringtheSecondWorldWar(1939～1945)resultedinanenormousdemandforittobeproducedinquantity.Upuntilthenithadonlybeenproducedinsmallamountsonthesuceofthefermentationbrothinmilkbottles!AnenormousR&DeffortjointlyintheU.S.andtheU.K.resultedintwomajorimprovementstotheprocess.FirstlyadifferentstainofthemouldgavemuchbetteryieldsthantheoriginalPenicilliumnotatum.Secondlythemajorprocessdevelopmentwastheintroductionofthedeepsubmergedfermentationprocess.Herethefermentationtakesplacethroughoutthebroth,providedsterileairisconstantly,andvigorously,blownthroughit.Thishasenabledtheprocesstobescaledupenormouslytomodernstainlesssteelfermentershavingacapacityinexcessof50000liters.Itissalutarytonotethatinthefirstworldwar(1914～1919)moresoldiersdiedfromsepticemiaoftheirwoundsthanwereactuallykilledoutrightonthebattlefield!

Penicillin能预防战争中因伤口感染引发的败血症，因而在第二次世界大战（1939-1945）中，penicillin的需求量非常大，需要大量生产。而在那时，penicillin只能用在瓶装牛奶表面发酵的方法小量的生产。英国和美国投入了巨大的人力物力联合进行研制和开发，对生产流程做出了两个重大的改进。首先用一个不同的菌株—黄霉菌代替普通的青霉，它的产量要比后者高得多。第二个重大的流程开发是引进了深层发酵过程。只要在培养液中持续通入大量纯化空气，发酵就能在所有部位进行。这使生产能力大大地增加，达到现代容量超过5000

升的不锈钢发酵器。而在

第一次世界大战中，死于伤口感染的士兵比直接死于战场上的人还要多。注意到这一点不能不让我们心存感激。Processdevelopmentforanewproductdependsonthingssuchasthescaleonwhichitistobemanufactured,theby-productsformedandtheirremoval/recovery,andrequiredpurity.Datawillbeacquiredduringthisdevelopmentstageusingsemi-technicalplant(upto100literscapacity)whichwillbeinvaluableinthedesignoftheactualmanufacturingplant.Iftheplantistobeaverylargecapacity,continuouslyoperatingone,e.g.petrochemicalorammonia,thenapilotplantwillfirstbebuiltandoperatedtotestouttheprocessandacquiremoredata,thesesemi-technicalorpilotplantswillberequiredfortesting,e.g.,apesticide,orcustomerevaluation,e.g.,anewpolymer.