Abstract
BackgroundIrpex lacteus, a versatile lignin-degrading fungus with various extracellular enzymes, has been widely used for biological pretreatment. However, most studies have focused on the change of substrate structure after biological pretreatment, and the effect of these changes on the enzymatic hydrolysis, but the effect of byproducts from biological pretreatment process on subsequent enzymatic hydrolysis is not well understood.MethodsWe developed a biological pretreatment process with I. lacteus that can produce stimulatory byproducts that enhance the enzymatic hydrolysis of cornstalks.ResultsThe maximum hydrolysis yield of glucan (82%) was obtained after pretreatment for 28 days. The maximum reducing sugar yield decreased from 313.5 to 200.1 mg/g raw cornstalks after water-soluble byproducts of biological pretreatment were removed from pretreated cornstalks. The effect of byproducts on enzymatic hydrolysis was also investigated. We found that the hydrolysis efficiency of commercial cellulase preparation on cornstalks could be improved by water extracts from bio-pretreated cornstalks with hydrolytic enzyme activity and iron-reducing activity.ConclusionThe key finding suggested that byproducts from biological pretreatment play important roles in enhancing downstream hydrolysis, which might be attributable to hydrolytic enzymes and iron-reducing compounds produced by I. lacteus.
Highlights
Irpex lacteus, a versatile lignin-degrading fungus with various extracellular enzymes, has been widely used for biological pretreatment
The results indicated that I. lacteus was an efficient lignin-degrading fungus, able to produce a lignin-degradation yield of 37.6% after 42 days of pretreatment
The lignin and xylan degradation caused by I. lacteus can result in decreasing the recalcitrance of the cornstalks to enzymatic hydrolysis, but the glucan degradation increases the glucose loss during the pretreatment, it is important to achieve a balance between the increase in overall saccharification yield and the consumption of polysaccharides during the biological pretreatment
Summary
A versatile lignin-degrading fungus with various extracellular enzymes, has been widely used for biological pretreatment. The physical and chemical nature of the substrate can be altered by pretreatment processes, such as removal of lignin and hemicellulose, decreasing cellulose crystallinity and increasing surface area, resulting in improvement in hydrolysis efficiency [2,4,5]. Thermochemical approaches such as dilute acid and steam-explosion pretreatment can offer high fermentable sugar yields for biorefinery, but these processes usually require high temperatures and operating pressures [5,6]. Subsequent detoxification treatment of pretreated substrate is necessary to remove the inhibitors and enhance the bioconversion efficiency, but this increases the biorefinery cost and causes loss of soluble sugars [5,10]
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
