Production of thermostable beta-galactosidase from tyhermophilic fungi for use in low-lactose milk production

Download

index.pdf

Date

2006

Author

Soydan, Meltem

Metadata

Show full item record

Item Usage Stats

242
views

319
downloads

The aim of this research was the production of beta-galactosidase from thermophilic fungi for use in low lactose milk production or other possible applications. For this purpose, three thermophilic fungi Humicola insolens, Torula thermophila and Thermomyces lanuginosus were screened for lactase production. Highest lactase activity was observed in Thermomyces lanuginosus. The carbon source inducing highest extracellular lactase production in Thermomyces lanuginosus was determined as arabinose. When grown on arabinose T. lanuginosus produced two major lactase activity peaks, one being at day 4 (beta-galactosidase-A) and second starting following the initiation of biomass degradation at day 3 suggesting the existence of a cell wall-bound beta-galactosidase (beta-galactosidase-B). Maximum activity of the second enzyme was at day 10. Crude enzyme stored at 4ºC and -20ºC was stable over a period of one month. Optimum pH and temperature of crude enzyme were found as pH 6.8 and 65ºC. For concentration of extracellular enzyme, fractional ammonium sulfate precipitation with 60-85% salt was applied. Comparisons with commercial lactase obtained from Kluyveromyces lactis revealed that partially purified lactase from Thermomyces lanuginosus was 1.3 times more efficient in hydrolysis of lactose even at 30ºC which is optimum for Kluyveromyces lactis. Lactose hydrolysis was enhanced at higher temperatures and reached maximum at 50-60ºC giving 4.7 fold higher hydrolysis than Kluyveromyces lactis beta-galactosidase. Molecular weight of the second enzyme was determined as 156 kDa by gel filtration. Being an extracellular enzyme with optimum pH suitable for dairy processes, high thermotolerance and stability, this enzyme has a potential for commercial use.

Subject Keywords

General Technology (including alchemy).

URI

http://etd.lib.metu.edu.tr/upload/3/12607501/index.pdf
https://hdl.handle.net/11511/16398

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Organic acids production from cheese-whey Türkmenoğlu, Seçil; Demirer, Göksel Niyazi; Department of Environmental Engineering (2006) In this study, production of organic acids from cheese-whey was studied. Optimization of organic acids production was performed in semi-batch and batch reactors. Two sets of experiments were performed. First set of experiments were performed in semi-batch reactors for the optimization of organic loading rate (OLR) and hydraulic retention time (HRT). As a result of Set 1 experiments optimum OLR was found to be 15 g COD l-1. Second set of experiments were performed in batch reactors by using the optimum OLR f...
Vanadium and molybdenum incorporated mcm-41 catalysts for selective oxidation of ethanol Güçbilmez, Yeşim; Doğu, Timur; Department of Chemical Engineering (2005) In this study, V-MCM-41, MCM-41 and Mo-MCM-41 catalysts were synthesized by the one-pot alkaline and acidic synthesis methods. The as-synthesized catalysts were found to have high BET surface areas (430-1450 m2/g), homogeneous pore size distributions (2-4 nm), good crystalline patterns and high metal loading levels (Metal/Si atomic ratio in the solid = 0.01-0.16) as determined by the characterization studies. MCM-41 and Mo-MCM-41 catalysts were highly active in the selective oxidation of ethanol with conver...
Utilization of pretreated molasses for serine alkaline protease production with recombinant Bacillus species Calik, G; Pehlivan, N; Kalender, N; Ozdamar, TH; Çalık, Pınar (Informa UK Limited, 2003-05-01) Recombinant Bacillus amyloliquefaciens, Bacillus cereus, Bacillus subtilis , and Bacillus licheniformis were used for the production of serine alkaline protease (SAP) utilizing chemically and/or physically pretreated molasses. The highest enzyme activity was obtained with r- Bacillus subtilis , with the complex medium involving physically treated molasses having 20 kg m(-3) initial sucrose concentration in small-scale, agitation- and heating rate-controlled bioreactors at t=63 h. Effects of oxygen transfer ...
Production of thermophylic α-amylase from aspergillus sp. and its utilization for various applications Gazaloğlu, Mehmet; Hamamcı, Haluk; Department of Biotechnology (2017) The objective of this study was to scale up the production of thermophilic α-amylase and its use to obtain fermentable sugar as the main carbon source for microorganisms such as baker’s yeast and Lactobacillus casei. Aspergillus niger N402 was the strain used for determining the fermentation parameters (carbon and nitrogen source, fermentation volume/total flask volume ratio (FV/TFV), pH & temperature of the fermentation and spore inoculum level.) Different strains (Am13, AmC18, and AmC28) were also tested ...
Use of biodiesel byproduct crude glycerol as the carbon source for fermentation processes by recombinant Pichia pastoris Celik, Eda; Ozbay, Nalan; OKTAR, NURAY; Çalık, Pınar (American Chemical Society (ACS), 2008-05-07) The aim of this study is to investigate the efficiency of using crude glycerol, the main byproduct of biodiesel industry, directly in the production media of Pichia pastoris fermentation processes. Different biodiesel synthesis conditions were examined, that is, transesterifications of canola, corn, soybean, and sunflower oils, with pure methanol in a molar ratio of 1:6 or 1:3, using 1% or 0.5% (w/v) NaOH as the catalyst. Among these, canola oil-derived glycerol served as the most favorable carbon source, a...

Citation Formats

M. Soydan, “Production of thermostable beta-galactosidase from tyhermophilic fungi for use in low-lactose milk production,” M.S. - Master of Science, Middle East Technical University, 2006.