| Author | Guo, Xuan |
| Call Number | AIT Thesis no.AE-96-11 |
| Subject(s) | Fermentation
|
| Note | A thesis submitted in partial fulfillment of the requirements
for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | One-step direct fermentative production of lactic acid from different starch sources using L. amylovorus was studied compared to two-step fermentation (saccarification followed by fermentation) using L. delbrueckii from starch in terms of lactic acid yield and productivity. Tuber starch like cassava and potato starch (1 %) gave poor lactic acid production at 4.72 and 4.42 g/L concentration, while cereal starch like corn. rice and wheat starch (1 %) gave lactic acid production at 10.05, 7.819 and 7.85 g/L respectively. Amylase enzyme activity was not the limiting factor during cassava starch fermentation as it was produced in sufficient quantity. Glucose repression occurs when glucose concentration is above 1 %. however. glucose accumulation during fermentation of cassava starch was less than 1 %. Vitamin B complex. calcium ion. yeast extract level and pH were found no significant effect on lactic acid production from cassava starch. Combination of peptone. beef extract and yeast extract can improve the lactic acid production to 8.28 g/L with conversion rate of 74.6% compared to 4.72 g/L with conversion rate of 42.5% from 1 % cassava starch. This result shows that there are some components present in corn starch, which is similar to peptone or beef extract. can stimulate the lactic ac id production. One-step fermentation can reduce the total time to half for lactic ac id production from starch compared to a two-step fermentation. It also eliminates the cost of enzyme associated to starch hydrolysis and reduces the number of reactors involved in the entire process. |
| Year | 1996 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Rakshit, Sudip Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Jindal, Vinod Kumar;Stevens, Willem Frans;Vincent, Jean-Claude; |
| Scholarship Donor(s) | State Education Committee of China; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1996 |