Ahmad Anas Nagoor Gunny

Potential halophilic cellulases for in situ enzymatic saccharification of ionic liquids pretreated lignocelluloses

Ionic liquids (ILs) have been used as an alternative green solvent for lignocelluloses pretreatment. However, being a salt, ILs exhibit an inhibitory effect on cellulases activity, thus making the subsequent saccharification inefficient. The aim of the present study is to produce salt-tolerant cellulases, with the rationale that the enzyme also tolerant to the presence of ILs. The enzyme was produced from a locally isolated halophilic strain and was characterized and assessed for its tolerance to different types of ionic liquids. The results showed that halophilic cellulases produced from Aspergillus terreus UniMAP AA-6 exhibited higher tolerance to ILs and enhanced thermo stability in the presence of high saline conditions.

Applicability evaluation of Deep Eutectic Solvents–Cellulase system for lignocellulose hydrolysis

Deep Eutectic Solvents (DESs) have recently emerged as a new generation of ionic liquids for lignocellulose pretreatment. However, DESs contain salt components which tend to inactivate cellulase in the subsequent saccharification process. To alleviate this problem, it is necessary to evaluate the applicability of the DESs-Cellulase system. This was accomplished in the present study by first studying the stability of cellulase in the presence of selected DESs followed by applicability evaluation based on glucose production, energy consumption and kinetic performance. Results showed that the cellulase was able to retain more than 90% of its original activity in the presence of 10% (v/v) for glycerol based DES (GLY) and ethylene glycol based DES (EG). Furthermore, both DESs system exhibited higher glucose percentage enhancement and lower energy consumption as compared to diluted alkali system. Among the two DESs studied, EG showed comparatively better kinetic performance.

Improvement of halophilic cellulase production from locally isolated fungal strain

Halophilic cellulases from the newly isolated fungus, Aspergillus terreus UniMAP AA-6 were found to be useful for in situ saccharification of ionic liquids treated lignocelluloses. Efforts have been taken to improve the enzyme production through statistical optimization approach namely Plackett–Burman design and the Face Centered Central Composite Design (FCCCD). Plackett–Burman experimental design was used to screen the medium components and process conditions. It was found that carboxymethylcellulose (CMC), FeSO4·7H2O, NaCl, MgSO4·7H2O, peptone, agitation speed and inoculum size significantly influence the production of halophilic cellulase. On the other hand, KH2PO4, KOH, yeast extract and temperature had a negative effect on enzyme production. Further optimization through FCCCD revealed that the optimization approach improved halophilic cellulase production from 0.029 U/ml to 0.0625 U/ml, which was approximately 2.2-times greater than before optimization.

Ionic Liquids: Green Solvent for Pretreatment of Lingnocellulosic Biomass

Green technology has become the primary concern of nations around the world. In-line with this concern, lignocellulosic biomass is often advocated as significant starting material for a greener production. However, the current biomass conversion cannot be considered as green due to the use of acid or alkaline during its pretreatment. An introduction of ionic liquids (ILs) as replacement of acids or alkaline for the pretreatment of lingo-cellulosic materials is gaining interest due to their minimal waste, nonvolatility and low toxicity and therefore considered green. This paper discusses the benefits of ILs as a green solvent for pretreatment of lignocellulosic biomass.

Fourier transform infrared spectroscopy (FTIR) analysis of paddy straw pulp treated using deep eutectic solvent

This study focus on Fourier Transform Infrared Spectroscopy (FTIR) analysis of paddy straw pulp treated using deep eutectic solvent (DES). DES was synthesized using potassium carbonate and glycerol at different molar ratio under normal atmospheric pressure. Pretreatment of lignocellulosic biomass was carried out at temperature of 120°C for 60 minutes under mass ratio of paddy straw to DES 1:9. The chemical structures of the untreated paddy straw and paddy straw pulp treated with different molar ratio of DES were analyzed using FTIR. The characterization result from FT-IR spectra indicated that the potassium carbonate-glycerol DES deconstructed the structures of paddy straw by removing lignin and hemicellulose during the pulping process. The peak intensity that occurs at region between 900 cm−1 and 1500 cm−1 shows that the presence of elevated level of cellulose after lignocellulosic pulping. From FT-IR analysis, DES could not remove the functional group of lignin and hemicellulose completely but yet expos...

Effect of structural changes of lignocelluloses material upon pre-treatment using green solvents

The Malaysia Biomass strategy 2020 stated that the key step of biofuel production from biomass lies on the pretreatment process. Conventional ‘pre-treatment’ methods are ‘non-green” and costly. The recent green and cost-effective biomass pretreatment is using new generation of Ionic Liquids also known as Deep Eutectic Solvents (DESs). DESs are made of renewable components are cheaper, greener and the process synthesis are easier. Thus, the present paper concerns with the preparation of various combination of DES and to study the effect of DESs pretreatment process on microcrystalline cellulose (MCC), a model substrate. The crystalline structural changes were studied using using X-ray Diffraction Methods, Fourier Transformed Infrared Spectroscopy (FTIR) and surface area and pore size analysis. Results showed reduction of crystalline structure of MCC treated with the DESs and increment of surface area and pore size of MCC after pre-treatment process. These results indicated the DES has successfully converte...

Enhanced halophilic lipase secretion by Marinobacter litoralis SW-45 and its potential fatty acid esters release

An approach was made to enhance the halophilic lipase secretion by a newly isolated moderate halophilic Marinobacter litoralis SW‐45, through the statistical optimization of Plackett‐Burman (PB) experimental design and the Face Centered Central Composite Design (FCCCD). Initially, PB statistical design was used to screen the medium components and process parameters, while the One‐factor‐at‐a‐time technique was availed to find the optimum level of significant parameters. It was found that MgSO4 · 7H2O, NaCl, agitation speed, FeSO4 · 7H2O, yeast extract and KCl positively influence the halophilic lipase production, whereas temperature, carbon source (maltose), inducer (olive oil), inoculum size, and casein‐peptone had a negative effect on enzyme production. The optimum level of halophilic lipase production was obtained at 3.0 g L−1 maltose, 1% (v/v) olive oil, 30 °C growth temperature and 4% inoculum volume (v/v). Further optimization by FCCCD was revealed 1.7 folds improvement in the halophilic lipase production from 0.603 U ml−1 to 1.0307 U ml−1. Functional and biochemical characterizations displayed that the lipase was significantly active and stable in the pH ranges of 7.0–9.5, temperature (30–50 °C), and NaCl concentration (0–21%). The lipase was maximally active at pH 8.0, 12% (w/v) NaCl, and 50 °C temperature. Besides, M. litoralis SW‐45 lipase was found to possess the promising industrial potential to be utilized as a biocatalyst for the esterification.