Degradation of bamboo lignocellulose by bamboo snout beetle Cyrtotrachelus buqueti in vivo and vitro: efficiency and mechanism

Abstract

Background As an important biomass raw material, the lignocellulose in bamboo is of significant value in energy conversion. The conversion of bamboo lignocellulose into fermentable reducing sugar, i.e. the degradation of bamboo lignocellulose, is an important step in lignocellulose conversion. However, little research has focussed on excavating the enzymes and microbes that are related to the degradation of bamboo lignocellulose, which is important for its utilisation. This study used Cyrtotrachelus buqueti (bamboo snout beetle) to evaluate the efficiency of bamboo lignocellulose degradation. Results RNA sequencing was conducted to sequence the transcriptome of the insect before and after feeding on bamboo shoots. The expression levels of genes encoding several carbohydrate-active enzymes, such as endoglucanase ( evgtrinloc27093t1 and evgtrinloc16407t0 ) and laccase ( evgtrinloc15173t0 and evgtrinloc11252t0 ), were found to be upregulated after feeding. Faecal component analysis showed that the degradation efficiencies of cellulose, hemicellulose and lignin were 61.82%, 87.65% and 69.05%, respectively. After 6 days of co-culture with crude enzymes in vitro, the degradation efficiencies of cellulose, hemicellulose and lignin in bamboo shoot particles (BSPs) were 24.98%, 37.52% and 26.67%, respectively. These results indicated that lignocellulosic enzymes and related enzymes within the insect itself co-degraded bamboo lignocellulose. These finding can potentially be used for the pre-treatment and enzymatic hydrolysis of bamboo lignocellulose. Conclusion Our results showed that intestinal digestive enzymes from C. buqueti degraded bamboo shoot lignocellulose both in vivo and in vitro. In addition, the expression levels of many carbohydrate-active enzyme (CAZyme) genes were upregulated in the transcriptome, including those for cellulase, xylanase and ligninase genes. Therefore, we proposed a scheme for applying the lignocellulolytic enzymes from C. buqueti to degrade bamboo lignocellulose using genetic, enzymatic and fermentation engineering techniques to overexpress the lignocellulolytic enzymes genes in vitro and obtain large quantities of enzymes that could efficiently degrade bamboo lignocellulose and be used for lignocellulose bioconversion. Electronic supplementary material The online version of this article (10.1186/s13068-019-1406-y) contains supplementary material, which is available to authorized users.

Integrated Analysis of Metabolome and Transcriptome of Bambusa emeiensis Shoots in Response to Bamboo Snout Beetle Cyrtotrachelus buqueti (Coleoptera: Curculionidae)

“…As products of photosynthesis, carbohydrates are the main source of stored energy for host plants and insect herbivores. In our previous study, we found that C. buqueti had a large scale of carbohydrate-active enzyme genes and very high degradation efficiency for the lignocellulose of B. emeiensis, and the lignocellulose of B. emeiensis was mainly composed of lignin, cellulose and hemicellulose, the three components of which were mainly sugars and their derivatives [17,18]. This study further explored the role of starch and sucrose metabolism related to carbohydrate in B. emeiensis based on transcriptome and metabolome association analysis.…”

“…pabularia) had a common mechanism of induction of changes in metabolites under methyl jasmonate induction and Cabbage Looper (Trichoplusia ni Hübner) feeding stress, implying that it is useful for pest control and nutritional quality of kale [15] B. emeiensis is widely distributed in Southwest China and is a plant with high economic value that is currently used in papermaking, landscaping and environmental protection [16]. In our previous study, we identified a large number of carbohydrate genes in C. buqueti [17], analyzed the ability of C. buqueti to degrade B. emeiensis lignocellulose, and explored the potential of using B. emeiensis for bioenergy conversion [18]. In the process, we learned that C. buqueti is a B. emeiensis specialist insect that severely damages and inhibits the development of bamboo shoots and affects the bamboo success rate of B. emeiensis.…”

Analyzing the Substrate Specificity of a Class of Long‐Horned‐Beetle‐Derived Xylanases by Using Synthetic Arabinoxylan Oligo‐ and Polysaccharides

“…This neglect is mostly due to the fact that relative to insects, microorganisms are easier to get access to and to cultivate in the laboratory. With more than 130 000 species, each of whose respective genomes harbor on average more than 10 genes encoding various PCWDEs, Phytophaga beetles represent the largest, under‐investigated pool of novel enzymes with potential use in the generation of biofuels …”

Comparative genomic and secretomic characterisation of endophytic Bacillus velezensis LC1 producing bioethanol from bamboo lignocellulose

“…The bamboo materials were sampled from the bamboo botanical garden of the Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, China. The bamboo powders were prepared as described by Luo et al [67]. BP samples were treated with 3% (w/w) Tween-80 to enhance alkali pretreatment efficiency.…”