TY  - THES
TY  - BOOK
T1  - Separation of alpha amylase from red pitaya peel through membrane filtration
A1  - Nurelyzurina Sukri,
LA  - English
UL  - http://discoverylib.upm.edu.my/discovery/Record/589248
AB  - Amylase is one of the most major important enzymes which is largely used in various industries. About 25% of the world's enzyme production is accounted by amylase. One of the natural sources of amylase is pitaya. Hence, this research studied the utilization of red pitaya for the separation of a-amylase using membrane-based process. The research was performed in 2 phases; (1) Characterization of the pitaya flesh and peel properties to relate with the membrane filtration process; and (2) Separation of a-amylase from red pitaya peel via membrane-based process. The findings showed that pitaya consisted of 78% flesh and 22% peel, with both having a-amylase specific activity of 0.24 and 0.09 U/mg protein, respectively. Besides, this study found that the flesh extract have higher pH value (5.39), total solid (3.97%), protein content (0.74 mg/ml) and enzyme activity (0.18 U/ml) compared to the peel extract with pH value (4.39), total solid (1.42%), protein content (0.43 mg/ml) and enzyme activity (0.04 U/ml). However, a presence of larger particle size distribution was found in the peel extract compared to the flesh counterpart. Based on the rheological properties of the fruit, the crude extracts of flesh parts indicate the need for the membrane process to be performed at acidic pH (pH 2), while for peel extract at its initial pH (pH 4.39) a successful filtration process. Extracts of both parts have a low viscosity value at high processing temperature, however the enzyme denaturation might occur, hence it is recommend for the filtration process to be performed at the room temperature. Since the peel of the red pitaya contains appreciable amount of a-amylase and is considered as waste in the industry, it was selected as the raw material for the membrane-based separation of a-amylase in the second phase of this study. The amylase separation was caried out using two stage polymeric ultrafiltration (UF) system
involving 100kDa and followed by 10kDa pol5rmeric membrane. In the UF stage 1,
78.8o/oenzyme recovery was retained by the UF process. An increment in amylase purity
up to 2.1-fold was observed in the UF stage 2. This obtained purification fold is within
the requirement of targeted purity. The permeate flux values for UF stages 1 and 2 were
11.6 and 6.2 kglm2h. respectively. Flux declination observed during UF process of
pitaya peel extract at both stages is totally influenced by the fouling phenomenon, most
probably because of the polysaccharide component including pectin. Based on the
regression of different fouling models, the cake formation on the entire membrane
surface has been identified as the main cause ofthe fouling in this study.
CN  - FK 2020 54
ER  -