Spent Sulphite Liquor (SSL) derived mainly from hardwoods, was used as enrichment to isolate microorganisms able to utilize the liquor for SCP production. Among the seven types of yeasts and ten types of fungi isolated, two strains of Candida krusei, two strains of Candida rugosa and an unidentified fungus (F-20) were characterized further. Optimal conditions of biomass production were obtained (pH 6.0, 28(DEGREES)C, SSL diluted with water 1:1, addition of 0.2% NaH(,2)PO(,4)). As a result of optimization, efficiencies of conversion ranged from 25% for C. krusei, to 44% for C. rugosa. The yeast species grown in mixed cultures increased the biomass production to 52.8%. Intraspecific hybridization by protoplast fusion of auxotrophic mutants of C. rugosa produced fused variants able to increase biomass production to efficiencies of conversion up to 55.9%. / The cells of the fused variants were larger than those of the parental types, resulting in faster sedimentation during centrifugation. / The regeneration of protoplasts from C. rugosa was affected by the length of incubation in the protoplasting solution. Optimal regeneration was found after 30 min of incubation. Mannitol was shown to be a better osmotic stabilizer than sorbitol for the regeneration of protoplasts from C. rugosa in MMA supplemented with amino acids. / The protein content of C. krusei, C. rugosa and its fused variants and the fungus F-20 was 44-55%; carbohydrate content, 15.7-21.5%; nucleic acid, 3.6-5.8%; and lipid, 0.8-3.8%. A good amino acid profile was obtained with one of the fused variants, except for the low content of methionine. / The protein quality (calculated PER) of C. rugosa ranged from 1.32 for the wild type to 1.50 for fused variants. The initial BOD was reduced by 80% after the yeast growth in SSL.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.68622 |
| Date | January 1981 |
| Creators | Silberstein, Alexander Michael. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Microbiology) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000137735, proquestno: AAINK54914, Theses scanned by UMI/ProQuest. |
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