Capsaicin (flavour indicator) and ascorbic acid (vitamin C, freshness indicator) were simultaneou... more Capsaicin (flavour indicator) and ascorbic acid (vitamin C, freshness indicator) were simultaneously extracted from fresh chillies and quantified.
Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media fo... more Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10-40wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.
Ionic liquids can be used as non-volatile, tunable solvents, extractants and electrolytes. This w... more Ionic liquids can be used as non-volatile, tunable solvents, extractants and electrolytes. This work investigates their ability to extract an organic analyte, capsaicin, from fresh Capsicum annuum Bird's eye chilli peppers (also known as Thai chillies), followed by the electroanalytical quantification of the extracted analyte. Ascorbic acid (vitamin C) was also extracted and quantified. Two ionic liquids were identified to extract capsaicin from fresh chilli more effectively than the conventional ethanol-based process; the inherently basic 1-ethyl-3-methylimidazolium acetate, [Emim][OAc], and the inherently acidic 1-ethyl-3-methylimidazolium hydrogen sulfate, [Emim][HSO 4 ]. The ionic liquid extracts could be electrochemically quantified using a bare glassy carbon electrode either in the pure ionic liquid (one pot extraction and quantification) or after dilution with water/ ethanol to assist resolution of the capsaicin (flavour indicator) and ascorbic acid (freshness indicator) features.
Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media fo... more Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60 wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60 wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10–40 wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60 wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.
Biomass pretreatment is a key first step in converting recalcitrant lignocellulosic biomass into ... more Biomass pretreatment is a key first step in converting recalcitrant lignocellulosic biomass into value-added products. Aqueous hydroxide solutions can be effective biomass pretreatment media, and the cation of the hydroxide salt can have an extremely significant effect upon the physicochemical behavior of the hydroxide solution. However, the cation effect has not been comprehensively investigated with respect to biomass pretreatment. Here, we investigated pretreatment of rice husks (from Oryza sativa) and show that the cation indeed has a significant effect upon downstream enzymatic hydrolysis of the cellulose (with cellulase). In particular, the ability of the solution to dissolve cellulose was negatively correlated with pretreatment effectiveness, as judged by the downstream glucose yield. This was observed by investigating aqueous solutions of lithium, potassium, cesium, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, and tetrahexylammonium hydrox-ide. Silica solubility was almost cation-independent, lignin solubility was moderately cation-dependent, while cellulose solubility was strongly cation-dependent. The rate of lignin extraction was inversely correlated with the size of the cation. As cellulose dissolution is a demanding chemical process, it initially limited the ability of the solution to disrupt the whole biomass, necessitated extensive washing of the pretreated rice husk, and still resulted in significant cation contamination downstream. Overall, lithium hydroxide was found to be the most effective hydroxide.
Capsaicin (flavour indicator) and ascorbic acid (vitamin C, freshness indicator) were simultaneou... more Capsaicin (flavour indicator) and ascorbic acid (vitamin C, freshness indicator) were simultaneously extracted from fresh chillies and quantified.
Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media fo... more Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10-40wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.
Ionic liquids can be used as non-volatile, tunable solvents, extractants and electrolytes. This w... more Ionic liquids can be used as non-volatile, tunable solvents, extractants and electrolytes. This work investigates their ability to extract an organic analyte, capsaicin, from fresh Capsicum annuum Bird's eye chilli peppers (also known as Thai chillies), followed by the electroanalytical quantification of the extracted analyte. Ascorbic acid (vitamin C) was also extracted and quantified. Two ionic liquids were identified to extract capsaicin from fresh chilli more effectively than the conventional ethanol-based process; the inherently basic 1-ethyl-3-methylimidazolium acetate, [Emim][OAc], and the inherently acidic 1-ethyl-3-methylimidazolium hydrogen sulfate, [Emim][HSO 4 ]. The ionic liquid extracts could be electrochemically quantified using a bare glassy carbon electrode either in the pure ionic liquid (one pot extraction and quantification) or after dilution with water/ ethanol to assist resolution of the capsaicin (flavour indicator) and ascorbic acid (freshness indicator) features.
Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media fo... more Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60 wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60 wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10–40 wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60 wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.
Biomass pretreatment is a key first step in converting recalcitrant lignocellulosic biomass into ... more Biomass pretreatment is a key first step in converting recalcitrant lignocellulosic biomass into value-added products. Aqueous hydroxide solutions can be effective biomass pretreatment media, and the cation of the hydroxide salt can have an extremely significant effect upon the physicochemical behavior of the hydroxide solution. However, the cation effect has not been comprehensively investigated with respect to biomass pretreatment. Here, we investigated pretreatment of rice husks (from Oryza sativa) and show that the cation indeed has a significant effect upon downstream enzymatic hydrolysis of the cellulose (with cellulase). In particular, the ability of the solution to dissolve cellulose was negatively correlated with pretreatment effectiveness, as judged by the downstream glucose yield. This was observed by investigating aqueous solutions of lithium, potassium, cesium, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, and tetrahexylammonium hydrox-ide. Silica solubility was almost cation-independent, lignin solubility was moderately cation-dependent, while cellulose solubility was strongly cation-dependent. The rate of lignin extraction was inversely correlated with the size of the cation. As cellulose dissolution is a demanding chemical process, it initially limited the ability of the solution to disrupt the whole biomass, necessitated extensive washing of the pretreated rice husk, and still resulted in significant cation contamination downstream. Overall, lithium hydroxide was found to be the most effective hydroxide.
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was thus heavily disrupted. Sulphuric acid hydrolysis of 60 wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10–40 wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60 wt% hydroxide solutions
was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.
was thus heavily disrupted. Sulphuric acid hydrolysis of 60 wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10–40 wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60 wt% hydroxide solutions
was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.