Expression of a Recombinant Lentinula edodes Xylanase by Pichia pastoris and Its Effects on Ruminal Fermentation and Microbial Community in in vitro Incubation of Agricultural Straws

Abstract

Agricultural straws, such as rice straw, wheat straw, and corn straw, are produced abundantly every year but not utilized efficiently in China. An experiment was conducted to determine the effects of recombinant xylanase on ruminal fermentation and microbial community structure in in vitro incubation of these straws. The recombinant xylanase from Lentinula edodes (rLeXyn11A) was produced in Pichia pastoris. The optimal temperature and pH for rLeXyn11A were 40°C and 4.0, respectively. The rLeXyn11A featured resistance to high temperature and showed broad temperature adaptability (>50% of the maximum activity at 20–80°C). Supplemental rLeXyn11A enhanced the hydrolysis of three agricultural straws. After in vitro ruminal incubation, regardless of agricultural straws, the fiber digestibility, acetate concentration, total volatile fatty acids (VFAs) production, and fermentation liquid microbial protein were increased by rLeXyn11A. Supplemental rLeXyn11A increased the ammonia-N concentration for corn straw and rice straw. High throughput sequencing and real-time PCR data showed that the effects of rLeXyn11A on ruminal microbial community depended on the fermentation substrates. With rice straw, rLeXyn11A increased the relative abundance of fibrolytic bacteria including Firmicutes, Desulfovibrio, Ruminococcaceae and its some genus, and Fibrobacter succinogenes. With wheat straw, rLeXyn11A increased the relative abundance of Ruminococcus_1 and its three representative species F. succinogenes, Ruminococcus flavefaciens, Ruminococcus albus. With corn straw, the fibrolytic bacteria Firmicutes, Christensenellaceae_R_7_group, Saccharofermentans, and Desulfovibrio were increased by rLeXyn11A. This study demonstrates that rLeXyn11A could enhance in vitro ruminal digestion and fermentation of agricultural straws, showing the potential of rLeXyn11A for improving the utilization of agricultural straws in ruminants.

Probiotic effect of ferulic acid esterase-producing Lactobacillus plantarum inoculated alfalfa silage on digestion, antioxidant, and immunity status of lactating dairy goats

“…In the current study, the dominant VFA product of ruminal fermentation from dairy goats in the Lp A1 and Lp MTD/1 treatments was acetate. The greater concentration and molar rate of acetate in Lp A1 treatment indicated that the efficiency of rumen fermentation for the diet was greater in the Lp A1 treatment than in the control (Lp MTD/1 treatment) ( Li et al., 2018 ). Moreover, there was no difference in the ratio of acetate to propionate between the 2 treatment groups, which might be related to the consistency of the composition of the 2 experimental diets ( Fimbres et al., 2002 ).…”

“…About 250 g/L (wt/vol) HPO 3 was mixed with ruminal fluid at a ratio of 1:5 and left overnight at 4 °C for the precipitation of true proteins. After centrifugation (4 °C; 15,000 ✕ g ; 15 min) and filtration with an 0.22-μm dialyzer, the VFA concentration of ruminal fluid was determined by a gas chromatograph (SP-3420A, Beijing Beifen-Ruili Analytical Instrument Co., Ltd, Beijing, China) that equipped with an AT-FFAP type capillary column (30 m × 0.32 mm × 0.5 μm) and a Flame Ionization Detector ( Li et al., 2018 ).…”

Microbiome and fermentation parameters in the rumen of dairy buffalo in response to ingestion associated with a diet supplemented with cysteamine and hemp seed oil

“…Members of the genus Acetobacter are important obligate anaerobes capable of both degrading readily fermentable carbohydrates and over‐oxidizing ethanol produced by Klebsiella to acetic acid (Kadere et al, 2008). Similarly, the fungal genus Pichia has a potential probiotic effect on cattle and can stimulate greater VFA potential (Fernandes et al, 2019); supplementation of recombinant xylanase produced by Pichia pastoris increased fibre digestibility, acetate concentration, total VFA production and microbial protein content (Li et al, 2018). The above results thus explain Acetobacter's significant positive correlations with Pichia , Klebsiella and Acinetobacter observed in the current study.…”

Production, purification, characterization and application of two novel endoglucanases from buffalo rumen metagenome

“…Although this agricultural straw fiber can be decomposed with ruminal microbiota, their ruminal degradability is still relatively low [7]. To enhance this straw fiber digestibility in rumen, adding exogenous fibrolytic enzymes (EFEs) with ruminant diets has been widely studied [8][9][10].…”

“…cazy. org), including GH5 to 10,12,26,44,45,48,51,60,61,74,124 and 131 [11]. Among these, GH5 is the largest family, and most of the GH5 cellulases are endoglucanases [11,12].…”