| dc.contributor.author | Tango, Martin Safari Akonaay. | en_US |
| dc.date.accessioned | 2014-10-21T12:35:40Z | |
| dc.date.available | 2000 | |
| dc.date.issued | 2000 | en_US |
| dc.identifier.other | AAINR13055 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/54769 | |
| dc.description | The possibility of improving the lactic acid concentration while reducing the effects of lactic acid and substrate inhibition on cell growth of Lactobacillus helveticus during fermentation of cheese whey under batch and continuous operations, using free and immobilized cells in a continuous mix 5L bioreactors were, investigated. The effects of temperature, initial lactose concentration, nutrient supplements addition and micro-aeration rates on the cell growth, lactose utilization and lactic acid production were studied during submerged batch fermentation. The effects of hydraulic retention time and initial lactose concentration on the cell growth, lactose utilization, lactic acid production and lactic acid yield were also investigated during continuous fermentation using free and immobilized cells. | en_US |
| dc.description | Three experimental setups were used in this study: (a) a free cell batch operation fermentation system, (b) a free cell continuous fermentation system and (c) an immobilized cell continuous fermentation system. Each experimental setup consisted of bioreactors, a specially designed water bath, a cheese whey feeding system, a pH control system, an aeration system and a data acquisition system. A Quick Basic (Microsoft Inc., version 4.5) environment was used to develop the software and operate the data acquisition system. The study was carried out in four phases: (a) design and development of the required experimental apparatus and data acquisition system, (b) experimental studies and laboratory analyses, (c) development of batch and continuous kinetic models for the prediction of cell, substrate and lactic acid concentrations and (d) verifying the validity of the developed kinetic models using experimental data obtained from batch and continuous experiments. | en_US |
| dc.description | For the temperature studies, only 50 g/L, initial lactose concentration was used in the continuous mix bioreactors and no pH control was provided. The temperature levels used were 23°C (with no control), 37°C (with no control), 37°C (with control) and 42°C (with control). Increasing the fermentation temperature from 23°C to 42°C (with no pH control), enhanced the lactose utilization and lactic acid production by 26.6% and 100%, respectively. However, with the optimum temperature control of 42°C, only 53.3% and 37.9% (of theoretical values) of lactose conversion efficiency and lactic acid yield were achieved in the absence of pH control. The study has shown the need for controlling both temperature and pH during batch lactic acid fermentation from cheese whey in order to achieve high substrate conversion efficiency and lactic acid yield. (Abstract shortened by UMI.) | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 2000. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Agriculture, General. | en_US |
| dc.subject | Engineering, Agricultural. | en_US |
| dc.title | Bioconversion of cheese whey to lactic acid in free and immobilized cell systems. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
