Effects of high hydrostatic pressure (HHP) on cellulose hydrolysis and cellulase activity, and its use for peanut hulls hydrolysis

Öztürk, Eylül
High hydrostatic pressure (HHP) technique has potential for food preservation purposes and HHP treatment can inactivate enzymes and/or increase their activity. Avicel, the commercial name of microcrystalline cellulose, is a commonly used substrate to observe the activity of cellulase. Cellulase activity is a crucial parameter for the production of alternative renewable fuels. Celluclast 1.5L, a mixture of enzymes, are used for the hydrolysis of cellulose and hemicellulose containing substances. Peanut hull (35% cellulose) as a lignocellulosic biomass is an appropriate material for conversion of the chemical feedstocks. The aim of this study is to observe different effects of HHP on substrate hydrolysis, and cellulose-hemicellulase (Celluclast) activity. Pressure and time were changed for HHP at the ranges of 0.1500MPa, and 5-15min, respectively, at 30oC. The results showed that hydrolysis of HHP-treated enzyme and HHP-treated enzyme-substrate solutions gave significantly higher reducing sugar content than the non-HHP-treated solution (p<0.05). However, no significant effect was observed between applied pressure levels of 100 and 500MPa (p>0.05). Additionally, the hydrolysis results demonstrated that pretreatment process was a necessary step to increase hydrolysis efficiency due to high lignin content of biomass. According to the Nuclear Magnetic Resonance (NMR) Relaxometry results, significant increases of T2 relaxation were observed with HHP-treated (100 MPa-5 min-30oC) samples due to an increase in hydrophilicity of the sample surface (p<0.05). Additionally, enzymatic hydrolysis led significant increase on the relaxation time (p<0.05). The effects of HHP, alkaline pretreatment and enzymatic hydrolysis were observed with the changes Fourier Transform Infrared (FTIR) spectra.


Effect of high hydrostatic pressure on the profile of proteins extracted from Betula pendula pollens
Altuner, Ergin Murat; Ceter, Talip; Alpas, Hami (2014-10-02)
High hydrostatic pressure (HHP) has high success potential in pollen protein extraction, but its effect on pollen protein profiles has not been studied yet. The aim of this study is to put forward whether HHP processing causes a change in the protein profiles extracted from pollens or not. In this study, proteins extracted from Betula pendula pollens were studied at 100, 200 and 300 MPa at room temperature for 5 min. In addition, the efficiency of three different extraction solvents, namely phosphate buffer...
Effects of ultrasound and high pressure on physicochemical properties and HMF formation in Turkish honey types
Onur, Ipek; Mısra, N. N.; Barba, Francisco J.; Putnık, Predrag; Lorenzo, Jose M.; Gökmen, Vural; Alpas, Hami (2018-02-01)
In industrial production, thermal processing of honey at 50 degrees C commonly induces liquefaction, i.e. it reduces the crystal count and viscosity and delays any subsequent crystallization. Unfortunately, thermal treatment can generate toxic 5-hydroxymethylfurfural (HMF), thereby resulting in quality reduction. Considering this, the present work aims at evaluating the influence of (two) processing technologies as alternatives to thermal processing of honey, namely high hydrostatic pressure (HHP; P = 220-3...
Effects of Isoflurane, Halothane, and Chloroform on the Interactions and Lateral Organization of Lipids in the Liquid-Ordered Phase
Türkyılmaz, Serhan; Regen, Steven L. (2011-12-06)
The first quantitative insight has been obtained into the effects that volatile anesthetics have on the interactions and lateral organization of lipids in model membranes that mimic "lipid rafts". Specifically, nearest-neighbor recogntion measurements, in combination with Monte Carlo simulations, have been used to investigate the action of isoflurane, halothane, and chloroform on the compactness and lateral organization of cholesterol-rich bilayers of 1,2-dipalmitoylsn-glycero-3-phosphocholine (DPPC) in the...
Effect of High Hydrostatic Pressure (HHP) Treatment on Physicochemical Properties of Horse Mackerel (Trachurus trachurus)
ERKAN ÖZDEN, Nuray; Uretener, Gonca; Alpas, Hami; Selcuk, Arif; Ozden, Ozkan; Buzrul, Sencer (2011-10-01)
The basic objective of this study was to determine the effect of high hydrostatic pressure (HHP; 220, 250 and 330 MPa), holding time (5 and 10 min) and temperature (7, 15 and 25 A degrees C) on some quality parameters of horse mackerel such as colour changes, thiobarbituric acid (TBA-i) and trimethylamine nitrogen (TMA-N), free amino acid content. HHP increased L (*) values of horse mackerel. The a (*) and b (*) of treated horse mackerel did not change significantly after HHP applications. After, HHP, TBA-i...
Effect of high hydrostatic pressure and high dynamic pressure on stability and rheological properties of model oil-in-water emulsions
BIGIKOCIN, Erman; Mert, Behiç; Alpas, Hami (2011-01-01)
Both static and dynamic high pressure applications provide interesting modifications in food structures which lead to new product formulations. In this study, the effects of two different treatments, high hydrostatic pressure (HHP) and high dynamic pressure (HDP), on oil-in-water emulsions were identified and compared. Microfluidization was selected from among the HDP homogenization techniques. The performance of each process was analyzed in terms of rheological modifications and emulsion stability improvem...
Citation Formats
E. Öztürk, “Effects of high hydrostatic pressure (HHP) on cellulose hydrolysis and cellulase activity, and its use for peanut hulls hydrolysis,” M.S. - Master of Science, Middle East Technical University, 2019.