Find en forsker – Københavns Universitet

Recovery of cellulase activity after ethanol stripping in a novel pilot-scale unit

Research output: Contribution to journalJournal articleResearchpeer-review

Pernille Anastasia Skovgaard, Børge Holm Christensen, Claus Felby, Henning Jørgensen

Recycling of enzymes has a potential interest during cellulosic bioethanol production as purchasing enzymes is one of the largest expenses in the process. By recycling enzymes after distillation, loss of sugars and ethanol are avoided, but depending on the distillation temperature, there is a potential risk of enzyme degradation. Studies of the rate of enzyme denaturation based on estimation of the denaturation constant K D was performed using a novel distillation setup allowing stripping of ethanol at 50-65°C. Experiments were performed in a pilot-scale stripper, where the effect of temperature (55-65°C) and exposure to gas-liquid and liquid-heat transmission interfaces were tested on a mesophilic and thermostable enzyme mixture in fiber beer and buffer. Lab-scale tests were included in addition to the pilot-scale experiments to study the effect of shear, ethanol concentration, and PEG on enzyme stability. When increasing the temperature (up to 65°C) or ethanol content (up to 7.5 % w/v), the denaturation rate of the enzymes increased. Enzyme denaturation occurred slower when the experiments were performed in fiber beer compared to buffer only, which could be due to PEG or other stabilizing substances in fiber beer. However, at extreme conditions with high temperature (65°C) and ethanol content (7.5 % w/v), PEG had no enzyme stabilizing effect. The novel distillation setup proved to be useful for maintaining enzyme activity during ethanol extraction.

Original languageEnglish
JournalJournal of Industrial Microbiology and Biotechnology
Volume41
Issue number4
Pages (from-to)637-646
Number of pages10
ISSN1367-5435
DOIs
StatePublished - 2014

    Research areas

  • Distillation, Enzyme recycling, Ethanol, Gas-liquid interfaces, Thermostable cellulases

ID: 131652107