Abstract
Landoltia punctata, a widely distributed duckweed strain with the ability to accumulate starch, was used as a novel feedstock for bioethanol production by Saccharomyces cerevisiae. To improve ethanol production, pectinase pretreatment was used to release much more glucose from L. punctata mash and the pretreatment conditions (enzyme loading, temperature and pretreatment time) for the duckweed were optimized by using a surface response design. The results showed that maximum glucose yield was 218.64 ± 3.10 mg/g dry matter, which is a 142% increase compared to the untreated mash, with a pectinase dose of 26.54 pectin transeliminase unit/g mash at 45 °C for 300 min. Pectinase pretreatment apparently changed the ultrastructure of L. punctata, as evidenced by scanning electron microscopy analysis. Further fermentation experiments were performed and 30.8 ± 0.8 g/L of ethanol concentration, 90.04% of fermentation efficiency and 2.20 g/L/h of productivity rate were achieved. This is the highest ethanol concentration reported to date using duckweed as the feedstock.
Highlights
Liquid biofuels, such as bioethanol, obtained from biomass are considered a promising alternative to fossil fuels in the effort to reduce greenhouse gas emissions and meet the strong global demand for energy
The galactose and arabinose suggested that the duckweed L. punctata could contain certain amount of pectin
The high protein content in L. punctata indicated that no other nitrogen source was necessary for the fermentation, which could help to reduce the total cost of ethanol production
Summary
Liquid biofuels, such as bioethanol, obtained from biomass are considered a promising alternative to fossil fuels in the effort to reduce greenhouse gas emissions and meet the strong global demand for energy. Bioethanol is mainly produced on an industrial scale from feedstocks containing starch and sugar, such as corn in the USA and sugarcane in Brazil [1]. These ethanol production modes have some inherent problems, including food security and agricultural land insufficiency [2]. Lignocellulosic biomass is regarded as a promising feedstock for ethanol production, there are still several obstacles (for example, the lack of an efficient, economical and environmentally friendly pretreatment process) to be overcome for economically feasible ethanol production [5]. Exploring new alternative feedstocks for ethanol production is an urgent topic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
