The Process of Xylanase Production from Bacillus pumilus RXAIII-5

Abstract

The optimum conditions for the growth or Bsclllns pnmllus RXAIII-5 (a potential xylanist producer) were nought. tbtst included trmpcraturc, pH, aeration. and agitation of the calturt batcb. Afterwards a mathematical modtl bawd on the parameter of cultivation klnttics was formulattd. At the uamc time, the rheology of the fluid a d COT battcrlal crltlvatlon in a biortactor was studied. The data obtained was used for cstlmatlng the 'scaling tip' of tnzyme production. The results of tbc study indicate thmt the optimum rondltion for proceraing In 50 ml Erltnmtytr flask art used temperature of 35 'C (308'K), pH 7, and an agitatlon rate or 140 rpm. The bigbest xylama8c activity aod Its sprciflr activity arc 297.132 U,ml-I mod 655.32 U.g-'profitin, rtnptctlvtly. Subsequent cxperimtntn In a blorcactor using all of tht experiment parnmtttrs mentioned above. except for the agi#ation ratt, #howl that the results art as follows. The highest rpcciClc growth war at 0,082 hour-' at an aeration and a~itacloa ratt of 0.5 vvm and 150 rpm. respectively. Based on the data of tht cultivation Irlneticn, the optlmum coaditiona for tbt ftrmcntation in Biostat ZL-bioreictor is 1 vvm and 200 tpm of atntion and agitation, respectlvrly. Tbc tMcltncy of substrate (Ypls) and of cell biomass (YI,,) to produce xylanase is 50.744 U.g-I mod 43.906 U.g-I, rerptctivtly. Tht eMciency of substrate to cell production (Y*,,) is 1.178g.g-I. The liquid culttvatlon-mrdlrm his non-Newtonian proptrtlts. Based on a mathematical model it is Connd that the conulsttary ladex (k congtant) mmd index of liquid bthavlor (11 value) are 0.179 g.crn-'.8ccond-' and 0.3212. resptttivrly. Btcoust the value or Ocm<l amd the conetant k>O. the culture liquid i s categorized as pseudo plastic one. The Rbtynold number (NRc) Is 6.9 x lff which indicates it has turbulent cltrmcttristics. From a cmlcut~tion it is louod that the power required to run a snitably slztd impeller ia 0.228 HP (Hornt Power) and the power ronsumption per unit volume i8 0.2265 HP.m4. All tbtsc valuer were urtd Tor ncaling up xylanasc production ia the biortattor.