Fermentation of sulfite spent liquor with Propionibacterium freudenreichii was done to produce volatile acids (acetic and propionic) and Vitamin B₁₂. It was found that in addition to producing these compounds some reduction in the pollution potential (COD) of this waste product was achieved. Better growth resulted if the spent liquor was first treated to remove lignin and calcium compounds. An existing spectrophotometry assay technique for measuring Vitamin B₁₂ content was modified for use in the presence of sulfite spent liquor. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate