Influence of Chelating Agents and Mechanical Pretreatment on Enzymatic Retting of Flax

Abstract

Adding chelating agents, i.e., oxalic acid and ethylenediamine-tetra-acetic acid (edta), substantially increases the retting effect on flax by the commercial enzyme products Ultrazym and Flaxzyme (Novo Nordisk), as shown by scanning electron microscopy, release of reducing sugars, and the Fried test. Degradation of pectin-rich citrus peel by these enzymes also increases with the addition of oxalic acid and edta, while citric acid has a low or insignificant effect. Oxalic acid at 50 mmol concentration reduces the amount of Flaxzyme required to effectively ret flax stems, according to the Fried test, by a factor of about 50. Retting with Flaxzyme and 50 mmol oxalic acid is completed in approximately half the time at 45°C, compared with that at 22°C. A mechanical pretreatment that crushes flax stems by pulling them over a surface at a 90° angle opens the flax structure and further increases the efficiency of enzymatic retting. These procedures appear to modify both the chemical and structural features of flax, and they reduce the time as well as the amount of enzyme required to ret flax, therefore improving technical efficiency and economic attractiveness at the commercial level.

Characterization of Flax Water Retting of Different Durations in Laboratory Condition and Evaluation of Its Fiber Properties

“…Each sample of 7 g of flax straws was rinsed with distilled water and then crushed twice with a 700 g rod to maximize retting performance by increasing the exposure of phloem regions along stems (Henriksson et al 1997). Subsequently, the sample was placed into a 250 mL glass bottle, and distilled water was added in a ratio of 1:33.…”

Purification and characterization of an exo-polygalacturonase secreted by Rhizopus oryzae MTCC 1987 and its role in retting of Crotalaria juncea fibre

“…Previous research has indicated that acidic pectins and Ca 2+ are located preferentially in the epidermal regions of Linum usitassimum (flax) (Rihouey et al 1995), contributing to the structural integrity of the stem and bast fibres. Therefore, chelators, such as EDTA, have the ability to remove Ca 2+ and enhance retting of flax (Henriksson et al 1997(Henriksson et al , 1999. The variability in the pectin content along with Ca 2+ in different fibres might influence the retting efficiency in the presence or absence of EDTA.…”

Treating bast fibres with pectinase improves mechanical characteristics of reinforced thermoplastic composites

“…Kompolti) for fibre production was grown according to 35°C and pH 4.5. EDTA was added to the incubation medium to destabilize pectins by complexing cell wall bound calcium [7,8,9]. After 4 h fibres were removed from solution, rinsed twice using tap water, centrifuged, and air-dried for 2 to 3 d. There were two independent preparations (prep1, prep2).…”