A therapeutic approach for treating diabetes is to decrease thepost-prandial hyperglycaemia. This is done by retarding the absorption of glucose through the inhibition of carbohydrate hydrolyzing enzymes, α-amylaseand α-glucosidase, in the digestive tract. Inhibition of both enzymes helpsto reduce the glucose level in the blood of a diabetic patient. This study was aimed to investigate the production of α-glucosidase and α-amylase inhibitors from local fruit wastes (honeydew skin, banana peel, and pineapple skin) using solid state fermentation. Each of the fruit wastes was fermented with three different types of white rot fungus Phenarochaete chrysosporium(PC), Panus tigrinusM609RQY(M6) andRO209RQY(RO2)for 7 days. Sampling was carried out starting from day 4 to day 7 to determine the enzyme inhibition activity. The samples were extracted using water prior to enzyme analysis. Most of the fruit samples showed varying degree of percentage inhibition activity depending on the sampling time. Extract of fermented banana peels with RO2 on day 4 showed the higherα-glucosidase inhibition (56.57±0.32%), followed byhoneydew extract fermented with the same fungus on the same day (39.68±0.05%). Extracts of each fruit wastesample fermented with PCshowed the least α-glucosidase inhibition (below 15%). Meanwhile for α-amylase inhibition activity, the extract from fermented honeydew skins with PCon day7 showed the highest inhibition activity i.e.98.29±0.63%. The least inhibition activity (43.37±0.54%) was observed in the extract from honeydew skins fermented withM6 on day 5. All positive resultsshowed that fruit wastes could be the alternative sourcesfor antidiabetic agent especially for α-amylase and α-glucosidase inhibitors.
Production cost of enzyme is largely determined by the type of the strain and raw material used to propagate the strain. Hence, selection of the strain and raw materials is crucial in enzyme production. For Glucose oxidase (GOx), previous studies showed Aspergillus terreus UniMAP AA-1 offers a better alternative to the existing sources. Thus, a lower production cost could be logically anticipated by growing the strain in a cheaper complex media such as molasses. In this work, sugar cane molasses, supplemented with urea and carbonate salt and a locally isolated strain Aspergillus terreus UniMAP AA-1 were used to produce a crude GOx enzyme in a small scale. A statistical optimization approach namely Response Surface Methodology (RSM) was used to optimize the media components for highest GOx activity. It was found that the highest GOx activity was achieved using a combination of molasses, carbonate salt and urea at concentration 32.51, 4.58 and 0.93% (w/v), respectively. This study provides an alternative optimized media conditions for GOx production using locally available raw materials.
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.
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 (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.