Volume 9 No. 6 November – December, 2004 ROMANIAN BIOTECHNOLOGICAL LETTERS – an international journal – CONTENTS 1.ELIZA PENA-LEONTE, LUCIA DUMITRIU, ILEANA GHITA, CIPRIAN DUMITRESCU, ANA MARIA FAGHI, MIHAELA LAZAROAE, GABRIELA TEODOSIUTreatment biotechnology of industrial wastewater with content of heavy metals ……………19072.Alexandra-Cristina BLAGA, Anca-Irina GALACTION, Elena FOLESCU, Dan CASCAVALSeparation of vitamin C by reactive extraction. 1.Mechanism and influencing factors ……………19173.Gabriela Bahrim, Teodor NegoităEffect of inorganic nitrogen and phosphorous sources on hydrolyase complex production by a selected Bacillus subtilis polar strain ……………19254.Gabriela Bahrim, Mariela GheteuImprovement of Aspergillus niger invertase production in stationary fermentative system …………… 19335.Anca-Irina GALACTION, Alexandra-Cristina BLAGA, Dan CASCAVALSeparation of vitamin C by reactive extraction. 2.Mathematical modeling of extraction process ……………19396.S. FLESCHIN, A.A. BUNACIU, MIHAELA SCRIPCARIUPreferable methods for immobilized biocatalysts in enzyme electrode construction ……………19477.S. FLESCHIN, A.A. BUNACIU, MIHAELA SCRIPCARIUBiochemical aspects of water pollution ……………1959 8.OANA IFTIME, RALUCA GHINDEA, TATIANA VASSU, ELENA SĂSĂRMAN, SIMONA SOARE, ROBERTINA IONESCUIdentification of yeasts in early stages of spontaneous fermentation of a red grape must ……………19659.Call for papers ……………197310.Instructions for Authors ……………1975 Cover: The Bucharest University Building