Degradation Of Pitch Components In Recycled Cardboard Production Process By Fungal Lipase

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2004Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2004Pitch maddelerinin biyolojik olarak arındırılması, kağıt endüstrisi için son yıllarda geliştirilmiş biyoteknolojik bir metoddur. Odun eksraktiflerinin kağıt makineleri üzerinde birikmesi, düşük kaliteli kağıt hamuru elde edilmesine ve blokajlara neden olur ki bu da üretimin durması, önemli ekonomik kayıplar, ürün kalitesini düşmesi ve zehirli atık su oluşması gibi sonuçlar doğurur Problemli pitch maddelerinin miktarı, kağıt üretimi esnasında biyolojik ve kimyasal işlemlerle azaltılabilir. Son yıllarda, bu problem doğal olarak pitch bileşkenlerini parçalayabilen ve odun üzerinde yaşayan funguslar kullanılarak aşılmaya çalışılmaktadır. Pitch parçalanmasında en başarılı olan funguslar Fusarium oxysporum ve Ophiostoma piliferum’dur. Bu funguslar triaçilgliseritleri hidrolize edebilen bir enzim olan lipaz üretir. Bu çalışmanın amacı, geri dönüşümlü kağıtta bulunan pitch bileşkenlerini analiz ederek bunları parçalamak için uygun bir yöntem geliştirmektir. Bu çalışmada, örneklerdeki triaçilgliserit, serbest yağ asidi, ester, hidrokarbon, mono ve diaçilgliseritler; bir gaz kromatografi cihazında ölçülmüştür. Kontrol olarak ticari enzimlerden Lipozyme IM, Lipozyme TL IM, Novozym 435 (Novo Nordisk) kullanılmıştır. Lipaz aktivitesi pH-stat cihazı ile ölçülmüştür. Hidroliz miktarını daha iyi saptamak amacıyla serbest yağ asitlerinin miktarı asit değeri tayini ile belirlenmiştir. Sonuçlar göstermiştir ki, F. oxysporum ve O. piliferum kültürlerinden elde edilen süpernatanlar geri dönüşümlü kağıt üretiminde pitch maddelerinin yok edilmesinde etkilidir.Biological pitch removal is a biotechnological method that has been developed recently for the paper and pulp industry. Accumulation of wood extractives in pulp and paper mills results in low-quality pulp and blockages that cause shutdowns of operations and important economic losses, reduces the quality of product and also create waste water toxicity. The amount of problematic pitch can be reduced by biological and chemical processes during paper production. In the recent years, this problem was tried to be solved by utilizing wood-dwelling fungi which naturally degrade pitch components. It has been shown that the two most successful fungi for pitch degradation are Fusarium oxysporum and Ophiostoma piliferum. These fungi produce lipases that hydrolyze triacylgyicerides. The aim of this study is to analyze the pitch components found in recycled paper to develop a suitable degradation method. Samples were analyzed on a GC to detect the amount of triacylgyicerides, free fatty acids, esters, hydrocarbons, mono and diacylglycerides. Commercial enzymes Lipozyme IM, Lipozyme TL IM, Novozym 435 from Novo Nordisk were used as controls. Lipase activity was assayed by using pH-stat. The amount of free fatty acids were also determined by acid value analysis in order to get a better quantification of the hydrolysis. Results demonstrated that F. oxysporum and O. piliferum growth medium supernatants can be efficiently used for pitch removal in recycled paper production.Yüksek LisansM.Sc

Enzymatic activity of a novel halotolerant lipase from Haloarcula hispanica 2TK2

A strain of Haloarcula hispanica isolated from Tuzkoy salt mine, Turkey exhibited extracellular lipolytic activity. Important parameters such as carbon sources and salt concentration for lipase production were investigated. Optimal conditions for the enzyme production from Haloarcula hispanica 2TK2 were determined. It was observed that the lipolytic activity of Haloarcula hispanica was stimulated by some of the carbon sources. The high lipase acitivity values were obtained in the presence of 2% (v/v) walnut oil (6.16 U/ml), 1% (v/v) fish oil (5.07 U/ml), 1% (v/v) olive oil (4.52 U/ml) and 1% (w/v) stearic acid (4.88 U/ml) at 4M NaCl concentration. Lipase was partially purified by ammonium sulfate precipitation and ultrafiltration. Optimal temperature and pH values were determined as 45°C and 8.0, respectively. Lipase activity decreased with the increasing salt concentration, but 85% activity of the enzyme was maintained at 5M NaCl concentration. The enzyme preserved 41% of its relative activity at 90°C. The partially purified lipase maintained its activity in the presence of surfactants such as Triton X-100 and SDS. Therefore, the lipase which is an extremozyme may have potential applications especially in detergent industry

Development of Potentiometric Lactate Biosensor Based on Composite pH Sensor

In this study, a micro-sized lactate sensitive biosensor based on polyvinylchloride, quinhydrone and graphite composite pH sensing platform was developed. Lactate oxidase was immobilized on the composite layer as the biorecognition element. Transformation reaction of lactate to pyruvate and hydrogen peroxide was the basis of this biosensor system. In the reaction, hydrogen peroxide undergoes to give hydronium ions into solution, and the pH sensitive membrane detects the adjunct hydronium ions potentiometrically. The surface of lactate biosensor based composite pH sensing matrice was first examined for electrochemical elucidation by using cyclic voltammetry and electrochemical impedance spectroscopy. A linear response in concentration range from 5x10(-5) to 1x10(-1) mol/L was obtained with a detection limit of 2x10(-5) mol/L. The lactate biosensor developed was successfully applied for highly precise and efficient determination of lactate in food preparations. The biosensor exhibited a fast response time (10 s), had good stability, and had an extended lifetime

A Novel Potentiometric Sensor for Determination of Neurotoxin β-N-Oxalyl-L-α, β-Diaminopropionic Acid

A novel potentiometric sensor based on ionophore (Cd(NH2CH2CH2OCH2CH2OCH2CH2NH2)Ag3(CN)5) for the determination of β-N-oxalyl-l-α, β-diaminopropionic acid (ODAP) is developed. The ODAP-selective membrane sensor demonstrates high sensitivity and short response time. The detection limit of the ODAP-selective membrane sensor is about 2×10-6 mol L-1 and the response time is shorter than 6 s. The linear dynamic range of the ODAP-selective membrane sensor is between ODAP concentrations of 1.0×10-2 and 1×10-6 mol L-1. The ODAP-selective membrane sensor exhibits good operational stability for at least one week in dry conditions at 4–6°C. It has a reproducible and stable response during continuous work for at least 10 h with a relative standard deviation of 0.28% (n = 18)