Ethanol production from halophyte Juncus maritimus using freezing and thawing biomass pretreatment

Abstract

a b s t r a c tJuncus maritimus contains (41.5 ± 0.3)% cellulose and (31.34 ± 0.2)% hemicellulose on dry solid (DS) basis and has the potential to serve as a low cost feedstock for ethanol production. Dilute acid or freezing/ thawing pretreatments and enzymatic saccharification were evaluated for conversion of halophyte plant from J. maritimus cellulose and hemicelluloses to monomeric sugars. The maximum concentration of released glucose from J. maritimus (53.78 ± 3.24) g L À1 ) by Freezing/thawing pretreatment and enzymatic saccharification (55 C, pH 5.0 and 48 h) using CellicCTec2 from Novozymes and (49.14 ± 5.24) g L À1 obtained by dilute acid pretreatment. The maximum yield of ethanol from acid pretreated enzyme saccharified J. maritimus hydrolyzate by Saccharomyces cerevisiae strain was (84.28 ± 5.11)% of the theoretical yield with a productivity of (0.88 ± 0.16)g L À1 h À1 . It was (90.87 ± 1.94)% of the theoretical yield with a productivity of (1.04 ± 0.10) g L À1 h À1 for freezing/thawing pretreated plant and enzymatic hydrolysis by CellicCTec2.

Microalgal biomass pretreatment for bioethanol production: a review

“…This pretreatment can be handled in cycles, i.e., the freeze-thaw process is repeated to increase cell disruption thereby, improving the extraction of carbohydrates or other compounds of interest, which are deeply rooted in cellular organelles. Although this pretreatment has been used only for cell disruption, but a recent study on certain lignocellulosic biomasses (which are more difficult to pretreat compared with microalgae biomass) performed by Smichi et al (2016) proved it to be an efficient alternative and a promising pretreatment for breaking biomass cells leading to a better accessibility of the contained polysaccharides for enzymatic attack. It should also be noted that this pretreatment does not produce any degradation compounds.…”

Facing the challenge of sustainable bioenergy production: Could halophytes be part of the solution?

“…A recent study assessed Juncus maritimus a salt marsh plant that can be used for producing lignocellulosic biomass, because its total carbohydrate content can reach up to 73%, with cellulose and hemicellulose representing approximately 41% and 31%, respectively, of the lignocellulosic biomass [ 102 ]. Tamarix aphylla , irrigated with reclaimed sewage (EC approximately 3 dS/m −1 ) to different salinity levels or with brine (EC approximately 7–10 dS/m −1 ), produced 52 t/ha and 26 t/ha, respectively, of organic biomass.…”

Wild Halophytic Phragmites karka Biomass Saccharification by Bacterial Enzyme Cocktail

“…Researchers are examining several new emerging halophytes for eco-friendly biofuel feedstocks that can grow in all climate regions. Hereby, halophytes, which produce plenty of biomass in a saline environment, constitute a potential candidate for bioenergy production without compromising human food sources ( Smichi et al, 2015 ). The data about the composition of some halophytes found in the coastline of Sindh and Balochistan, Pakistan, showed ∼25–30% of cellulose and ∼25–30% hemicellulose with less than 10% lignin content ( Abideen et al, 2011 ; Munir et al, 2021 ), which make them suitable candidates for biorefinery purposes.…”

“…Among various chemicals, dilute acid pretreatment has been reported for many glycophytes and halophytic biomass ( Smichi et al, 2014 ), as it offers several advantages, i.e., reduction of thermal degradation of polysaccharides, increased conversion of cellulose to sugars, and low inhibitor concentrations. While the freeze-thaw procedure has been adopted as a milder technique to pretreat halophytic mass ( Smichi et al, 2015 ), it neither releases any toxic chemicals nor requires any special equipment. The pretreated halophytic biomass can be converted into biofuels and other value-added products by biological conversion using enzymatic hydrolysis and microbial fermentation.…”