Pengaruh Pemerangkapan Enzim Alkalin Fosfatase ke dalam Silika dari Abu Sekam Padi terhadap Aktivitas Enzimatiknya

Abstract

A r t i c l e I n f o A b s t r a c tKeywords: Alkaline phosphatase, RHA, entrapment, silica, enzyme.Alkaline phosphatase was entrapment in silica from rice hull ash by sol-gel process. In this procedure, silica solution was exstracted from rice hull ash (RHA) by 1.5 N of sodium hydroxide. The 0.1 N of hydrochloride acid solution was added to decrease pH until 10. Alakline phosphatase (in tris-HCl buffer solution at pH: 8) was added to silica solution, placed in desicator until gel formed. Dry gel formed was immobilized enzyme. The catalytic properties and kinetic parameters both free enzyme in solution and immobilized enzyme was studied. Results showed that the optimal pH and temperature for the immobilized alkaline phosphatase in silica were 9.0 and 45•C, which were higher than those of the free form ( 8.5 and 40•C). It was found, at room temperature and pH 8.5, that the Michaelis-Menten constant (Km) was 7.50 mM and that specific activity was 0.051 U/mg enzyme for entrapment alkaline fosfatase, compared to a Km of 0.08 mM and specific activity 1.041 U/mg enzyme for free the alkaline phosphatase.A b s t r a k Kata kunci: Alkalin fosfatase, abu sekam padi, pemerangkapan, silika, enzim.Alkalin fosfatase telah diperangkap ke dalam silika dari abu sekam padi melalui proses sol-gel. Dalam prosedur ini, larutan silika dihasilkan melalui ekstraksi abu sekam padi menggunakan larutan natrium hidroksida 1,5 N. Larutan asam klorida 0,1 N ditambahkan untuk menurunkan pH larutan silika hingga 10. Alkalin fosfatase (dalam larutan buffer tris-HCl pH:8) ditambahkan ke dalam larutan silika, didiamkan di dalam desikator hingga terbentuk gel. Gel kering merupakan enzim terperangkap (terenkapsulasi). Parameter katalitik dan kinetik ditentukan baik untuk enzim bebas dalam larutan maupun untuk enzim terimobilisasi. Hasil menunjukkan bahwa pH dan suhu optimal untuk alkalin fosfatase terimobilisasi dalam silika adalah 9,0 dan 45•C, lebih tinggi dibandingkan dengan bentuk bebasnya (8,5 dan 40•C). Pada suhu kamar dan pH 8,5, konstanta Michaelis-Menten (Km) adalah 7,50 mM dan aktivitas spesifiknya adalah 0,051 U/mg enzim untuk alkalin fosfatase terenkapsulasi, sedangkan untuk alkalin fosfatase bebas dalam larutan berturut-turut 0,08 mM dan 1,041 U/mg enzim.

Encapsulation of Lipase Enzyme in Silica Gel Matrix from Rice Husk Ash and Transesterification Reaction Activity Test on Palm Oil

“…Lipase is one of the biocatalysts that can be used for transesterification reactions [9]. Researchers have successfully encapsulated enzymes in rice husk ash silica gel matrix using sol-gel techniques such as lipase [10], glucose oxidase (HRP-GOx) [11], alkaliphilic lipase [12], and alkali phosphatase [13]. Enzymes encapsulated in silica gel showed high activity compared to free enzymes, were easy to separate, and can be used repeatedly.…”