碩士 / 國立臺灣海洋大學 / 食品科學系 / 107 / Lactic acid is not only the main raw material of polylactic acid, but also widely used in industry such as pharmaceutical, food, and plastics industries. Green alga Ulva sp., which contains high amount of polysaccharides and proteins, has the potential to be an alternative substrate for lactic acid fermentation. This study intends to use green alga Ulva sp. for lactic acid fermentation. The encapsulation efficiency of immobilized Lactobacillus rhamnosus BCRC 10940 and BCRC 14068 were 84.0 ± 6.4% and 83.1 ± 5.0%, respectively, by using Poly-L-Lactic Acid Microtube Array Membrane (PLLA-MTAM). The yields of lactic acid in fermentation of MRS broth using immobilized Lb. rhamnosus BCRC 10940 and BCRC 14068 were 0.55 ± 0.01 and 0.58 ± 0.01 g/g sugar, respectively. In addition, by-product ethanol was also producted, the yields of ethanol were 0.20 ± 0.00 and 0.20 ± 0.00 g/g sugar, respectively. The Ulva sp. acid hydrolysate was prepared by acid hydrolysis and electrodialysis, in which contained 9.35 ± 0.07g/L of glucose, 39.27 ± 0.12 g/L of rhamnose. The MRS broth with rhamnose as carbon source was fermented by Lb. rhamnosus BCRC 10940 and BCRC 14068, Lb. rhamnosus BCRC 10940 was able to use rhamnose and produce lactic acid, the yields of lactic acid were 0.36 ± 0.11 g/g sugar, and the highest lactic acid production rate was 0.28 ± 0.01 g/L∙h; Lb. rhamnosus BCRC 14068 was unable to produce lactic acid from rhamnose. The results above indicated that Ulva sp. is not suitable as carbon source in the lactic acid fermentation using Lb. rhamnosus BCRC 10940 and BCRC 14068. Lb. rhamnosus BCRC 10940 and BCRC 14068 are also not suitable as strains for the fermentation aims high production of lactic acid. 12% (w/v) Ulva sp. powder, 15 U Cellulase/mL, 5.40 U Umamizyme/g Ulva sp., and hydrolysis for 48 hours were used to prepare the Ulva sp. enzymatic hydrolysate, and the free amino acid content was 103.06 ± 1.38 mM. The Ulva sp. enzymatic hydrolysate was fermented by Lb. acidophilus, the highest lactic acid production rate was 0.58 ± 0.04 g/L∙h, the yield of lactic acid was 0.86 ± 0.02 g/g sugar, and the highest count of viable Lb. acidophilus cells was 9.31 ± 0.03 Log CFU/mL. These results indicated that Lb. acidophilus grew well in the Ulva sp. enzymatic hydrolysate, and Ulva sp. could be used as a good nutrient supplementation for lactic acid fermentation, to replace the nitrogen source in the media and provide amino acids.
| Identifer | oai:union.ndltd.org:TW/107NTOU5253024 |
| Date | January 2019 |
| Creators | Hung, Chin-Chieh, 洪勤絜 |
| Contributors | Lin, Hong-Ting, 林泓廷 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 85 |
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