Lipopeptide produced from Bacillus sp. W112 improves the hydrolysis of lignocellulose by specifically reducing non-productive binding of cellulases with and without CBMs

Abstract

BackgroundSurfactants have attracted increasing interest for their capability to improve the enzymatic hydrolysis of lignocellulosic biomass. Compared to chemical surfactants, biosurfactants have a broader prospect for industrial applications because they are more environmentally friendly and more effective in some researches. Commercial cellulase preparations are mainly composed of endoglucanases (EGs) and cellobiohydrolases (CBHs) that possess carbohydrate-binding modules (CBMs). However, the effects of lipopeptide-type biosurfactants on enzymatic saccharification of lignocellulose and adsorption behaviors of cellulases with CBMs remain unclear.ResultsIn this study, we found that Bacillus sp. W112 could produce a lipopeptide-type biosurfactant from untreated biomass, such as wheat bran and Jerusalem artichoke tuber. The lipopeptide could enhance the enzymatic hydrolysis of dilute acid pretreated Giant Juncao grass (DA-GJG) by fungal and bacterial enzymes. The enhancement increased over a range of temperatures from 30 to 50 °C. Lipopeptide was shown to be more effective in promoting DA-GJG saccharification than chemical surfactants at low dosages, with a best stimulatory degree of 20.8% at 2% loading of the substrates (w/w). Lipopeptide increased the thermostability of EG and CBH in commercial cellulase cocktails. Moreover, the dual effects of lipopeptide on the adsorption behaviors of cellulases were found. It specifically lowered the non-productive binding of cellulases to lignin and increased the binding of cellulases to cellulose. In addition, we investigated the influence of lipopeptide on the adsorption behaviors of CBHs with CBMs for the first time. Our results showed that lipopeptide reduced the adsorption of CBM-deleted CBH to DA-GJG to a greater extent than that of intact CBH while the non-productive binding of intact CBH to lignin was reduced more, indicating that lipopeptide decreased the binding of CBMs onto lignin but not their combination with cellulose.ConclusionsIn this study, we found that lipopeptide from Bacillus sp. W112 promoted the enzymatic hydrolysis of DA-GJG at relative low loadings. The stimulatory effect could be attributed to increasing the cellulase thermostability, reducing non-productive adsorption of cellulases with CBMs caused by lignin and enhancing the binding of cellulases to cellulose.Electronic supplementary materialThe online version of this article (10.1186/s13068-017-0993-8) contains supplementary material, which is available to authorized users.

Marine Biosurfactants: Biosynthesis, Structural Diversity and Biotechnological Applications

“…Biosurfactants are also applicable to improve the degradation of complex biomass in so-called biorefinery processes to exploit alternative industrial resources. Here, their supplementation may enhance enzymatic lignocellulose degradation efficiency, probably by the improvement of substrate binding of the applied cellulases [212]. Another study reported increased hydrogen production from organic solid waste through surfactin and saponin supplementation [213].…”

Application of the biosurfactant produced by Bacillus velezensis MMB‐51 as an efficient synergist of sweet potato foliar fertilizer

“…For example, rhamnolipid biosurfactant produced by P. aeruginosa BWL1001 was used to accelerate the biodecolorization efficiency of azo dyes (Liu, You, et al, 2017); lipopeptide biosurfactant produced from Bacillus sp. W112 was applied to improve the hydrolysis of lignocellulose by specifically reducing nonproductive binding of cellulases (Liu, Zhu, et al, 2017); sophorolipid biosurfactant secreted from Rhodotorula babjevae YS3 exhibits antifungal activities against plant and human pathogens (Sen et al, 2017); biosurfactants produced by Bacillus licheniformis L20 and Achromobacter sp. A‐8 have been used to enhance oil recovery and bioremediation (Deng et al, 2020; Liu et al, 2021); biosurfactants secreted from P. aeruginosa SS14 and Bacillus tequilensis SDS21 showed anti‐biofilm activity (Borah et al, 2019; Singh & Sharma, 2020); biosurfactants produced by Bacillus nealsonii S2MT, B. subtilis LAMI005 and Pseudomonas sp.…”

“…Fourier transform infrared spectroscopy (FTIR) was performed to analyze the functional groups in BS‐51 (Liu, Zhu, et al, 2017). The lyophilized BS‐51 sample was milled and compressed with pure KBr powder, and the spectrum of BS‐51 was recorded using a Fourier transform infrared spectroscopy (Bruker Tensor 27) in a wave range from 600 to 4000 cm −1 .…”

“…At present, biosurfactants have been widely used in oil recovery (Datta et al, 2018), food processing (Ribeiro et al, 2020), and remediation of soil polluted by heavy metals or other pollutants (Guo & Wen, 2021; Machado et al, 2020). In addition, biosurfactants have also been applied to improve the enzyme catalytic degradation efficiency of stubborn pollutants or lignocellulosic substances by improving the contact efficiency between enzyme and substrate (Ahmad et al, 2021; Carolin, Kumar, Joshiba, et al, 2021; Liu, Zhu, et al, 2017). It is notable that some chemical surfactants like tween were employed to enhance the utilization of foliar fertilizers previously.…”

Altering the linker in processive GH5 endoglucanase 1 modulates lignin binding and catalytic properties

“…Accordingly, the CDs of different GH5 family members display different affinities for lignin, with binding being driven by electrostatic interactions or hydrogen bonding depending on the enzyme in question [10, 12, 19]. Many efforts have been devoted to the prevention of non-productive adsorption in enzymatic hydrolysis, such as changing pretreatment conditions [20, 21] or blocking the exposed lignin surface using bovine serum albumin (BSA) and additives [22–24]. A promising alternative approach would be engineering or discovering natural cellulases with low lignin-binding propensities, relying on a full understanding of enzyme–lignin interactions [17].…”