Production of fructooligosaccharides and galactooligosaccharides by immobilized enzymes

• Main Authors: Tzu-Chien Cheng, 鄭慈千
• Other Authors: Kow-Jen Duan
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/38740929876972932475

博士 === 大同大學 === 生物工程學系(所) === 93 === ABSTRACT We present the results of this study in the production of fructooligosaccharides (FOS) and galactooligosaccharides (GOS) by immobilized enzymes from sucrose and lactose solution. The β-frutofuranosidase and β-galactosidase were immobilized onto chitosan using tris (hydroxymethyl) phosphine (THP) as a coupling agent to produce fructooligosaccharides and galactooligosaccharides, respectively. Our results demonstrated the possible industrial application of the THP-immobilized β–frutofuranosidase and ��-galactosidase for continuous production of fructooligosaccharides and galactooligosaccharides at longer duration and higher temperature tolerance at 55 oC. Our study show the THP-immobilization has better thermal stability then the glutaraldehyde as a coupling agent. For the production of fructooligosaccharides, β–frutofuranosidase from Aspergillus japonicus (BCRC 930007) was immobilized onto chitosan using tris (hydroxymethyl) phosphine (THP) and glutaraldehyde as coupling agents to produce FOS. The optimal pH was 5.5 and the optimal temperature was 60oC for both free and two immobilized enzymes. The THP-immobilized β–frutofuranosidase retained more than 75 % activity after 11 batches (or days) of FOS production at 37oC. The THP-immobilized enzyme had higher reusability than that immobilized by glutaraldehyde. The Km for the free, THP-immobilized and glutaraldehyde-immobilized enzyme were 0.03 g/l (s.d.= 0.03), 0.06 g/l (s.d.= 0.05) and 0.05 g/l (s.d.= 0.03), respectively. The yield of FOS with the free enzyme from the sucrose solution (50 %, w/v) at 50 oC was 58 % and the THP-immobilized enzyme (48 %) is less than the free enzyme. For the production of galactooligosaccharides, the β-galactosidase was immobilized on to chitosan using tris (hydroxymethyl) phosphine (THP) as a coupling agent to produce galactooligosaccharides from lactose solution. Both the THP-immobilized and the free enzymes were maximally achieved at pH 5.0 and the optimal temperature was 55 oC. The THP-immobilized enzyme still can remain 70 % residual activity from 36 % (w/v) of lactose after 13 batches (or days) at 55oC. This show the THP-immobilized has better thermal stability. The yield of GOS with the free enzyme from the lactose solution (36 %, w/v) at 55 oC is 43 %, which is about the same as that with the THP-immobilized counterpart with 41 % yield.