Optimized Organosolv Pretreatment of Biomass Residues Using 2-Methyltetrahydrofuran and n-Butanol

Wheat straw and eucalyptus residues were pretreated in a biphasic system, constituted of butanol (n-butanol) or 2-methyltetrahydrofuran (2M-THF) and aqueous oxalic acid solutions. The pretreatments were carried out in a 300 mL Parr reactor (Autoclave Buchi Limbo-li®) with a solid load of 5 wt.%, the temperature in the range 140–180 °C, oxalic acid load from 0 to 10 wt.% and a duration of 30–90 min. The obtained slurry was then fractionated in three streams: the aqueous phase which contained solubilized hemicellulose, the organic phase which contained the solvated lignin, and the solid residue which contained cellulose. The solid was hydrolyzed using a commercial mix of enzymes to assess cellulose digestibility and glucose production. The pretreatment was optimized to maximize the purity of the cellulose and hemicellulose fractions and the glucose recovery as free sugar. The optimization was done by using an experimental design and response surface methodology. The mass flow details of the four optimized processes were obtained. In terms of biomass fractionation, butanol demonstrated significant advantages over 2M-THF in the same range of process conditions as shown by the recovery yield of free glucose which reached 98% of the theoretical value with butanol but was 67% with 2M-THF. Tests at low temperature and low enzyme loading highlighted the importance of the solvent choice over the operating conditions. 2M-THF showed interesting performances only in the delignification step, with 90% efficiency for the straw. Regarding the use of different feedstock, fractionation and recovery were generally higher for wheat straw than for eucalyptus wood residues.

PSVII-16 Effects of different forms of Cu on in vitro ruminal fermentation and digestibility of a lactation diet

Vistore® mineral products are hydroxychloride minerals that feature high metal content and improved bioavailability. This study was conducted to compare different sources of copper (Cu) on in vitro rumen fermentation parameters. Three ruminally-cannulated Jersey heifers were adapted to a lactation diet for two weeks before being used as donors. Three sources of Cu at 4 ppm: No supplemental Cu (CON), CuSO4, Vistore Cu, and another Cy hydroxychloride product (Vistore-competitor). The concentration of Cu in this study was selected from a titration study (0 to 8 ppm CuSO4) to identify the minimum concentration of CuSO4 affecting rumen fermentation. The lactation diet (TMR) was dried and ground to 1mm and used as the substrate. Rumen fluid was collected two hours after feeding. Substrate (0.5 g) was inoculated with 100 mL of a 3:1 McDougall’s buffer: ruminal fluid mixture at 39ºC for 24 h. Each treatment was run in triplicate and in three runs. Data were analyzed with R 4.0. The model included fixed effect of treatment and random effect of run. CuSO4 tended to increase lag time (0.78 vs -0.57 h, P = 0.06), reduced (P < 0.05) DMD (52.4 vs. 56.1%), cellulose digestibility (4.9% vs. 41.9%), isobutyrate molar % (0.58 vs. 0.78%) and NH3-N concentration (5.46 vs. 6.91 mg/dL). Vistore and Vistore-competitor maintained the fermentation and digestibility compared to CON. In general, Vistore Cu and Vistore-competitor maintained ruminal fermentation and digestibility parameters while negative effects of CuSO4 were observed. These results indicate different Cu mineral sources may affect the rumen differently.

Arabidopsis GELP7 is plasma membrane-localized acetyl xylan esterase, and its overexpression improves saccharification efficiency.

Acetyl substitution on the xylan chain is critical for stable interaction with cellulose and other cell wall polymers in the secondary cell wall. Xylan acetylation pattern is governed by Golgi and extracellular localized acetyl xylan esterase (AXE). We investigated the role of Arabidopsis clade Id from the GDSL esterase/lipase or GELP family in polysaccharide deacetylation. The investigation of the AtGELP7 T-DNA mutant line showed a decrease in stem esterase activity and an increase in stem acetyl content. We further generated overexpressor AtGELP7 transgenic lines, and these lines showed a decrease in xylan acetylation in comparison with wild type plants. Therefore, we have named this enzyme as AtAXE1. The subcellular localization studies showed that the AtAXE1 enzyme is secreted out, associated with the plasma membrane and involved in xylan de-esterification post-synthesis. The cellulose digestibility was improved in AtAXE1 overexpressor lines without pre-treatment, after alkali and xylanases pre-treatment. Furthermore, we have also established that the AtGELP7 gene is upregulated in the overexpressor line of AtMYB46, which is a secondary cell wall specific transcription factor. This transcriptional regulation can drive AtGELP7 or AtAXE1 to perform de-esterification of xylan in a tissue-specific manner.

Phenomenological Modeling of Formic Acid Fractionation of Sugarcane Bagasse by Integration of Operation Parameters as an Extended Combined Severity Factor

In order to more conveniently simulate and optimize the solubilization of sugarcane bagasse components during formic acid (FA) fractionation, an extended combined severity factor (CSFext) was defined to integrate various operation parameters as a single factor. Two phenomenological models based on Arrhenius and Logistic equations were further used to describe the phenomenological kinetics. Different data-processing methods were compared to fit the severity parameters and model constants. Both Arrhenius-based and Logistic-based models show satisfying fitting results, though the values of Arrhenius-based CSFext (A-CSFext) and Logistic-based CSFext (L-CSFext) were somewhat different under the same fractionation condition. The solubilization of biomass components increased with CSFext, but two distinct stages could be observed with inflection points at A-CSFext of 42 or L-CSFext of 43, corresponding to bulk and residual solubilization stages, respectively. For the enzymatic hydrolysis of cellulosic solids, the highest initial enzymatic glucan conversion (EGC@6h) was obtained at A-CSFext of 39–40 or A-CSFext of 40–41; however, for a long hydrolysis period (72 h), relatively high glucan conversion (EGC@72h) was observed at A-CSFext of 42–43 or A-CSFext of 43–44. Post-treatment for deformylation with a small amount of lime could help to recover the cellulose digestibility.

Kecernaan Serat dan Fermentasi Kulit Buah dan Pelepah Nipah Menggunakan Mikro Organisme Lokal (MOL)

This study aims: to determine the appropriate length of fermentation time for nipah fruit skin and nipah midrib so that the nutritional value and digestibility of cellulose and hemicellulose are increased. The study used a completely randomized design with 2 factor, namely: the type of material and the length of time of fermentation and was repeated 3 times. The first factor is the type of material: nipah fruit skin and palm fronds. Factor II, namely the lenght of fermentation time : 5 days, 10 days, 15 days and 20 hari hearts. Variables measured were crude fiber content, crude protein, cellulose digestibility and hemicellulose digestibility. The results showed that the digestibility of cellulose and hemicellulose digestibility of nipah fruit peels and palm fronds were significantly different (P<0,05) but the crude fiber and crude protein (MOL). In general, the digestibility of cellulose and hemicellulose inscreases with increasing fermentation time. The best digestibility occurred at 15 days of fermentation time for cellulose digestibility 64,69% and hemicellulose digestibility 72,43%. The interaction between nipah fruit skin and fermentation time of 20 days showed optimal results on hemicellulose digestibility.

Daniellia oliveri as a fodder tree for small ruminant and the interaction of its tannin with ruminal ammonia

Daniellia Oliveri was examined as a potential fodder for small ruminant, using nine castrated and ruminally fistulated West African Dwarf sheep (29 kg BW) to determine rumen ammonia and nutrient digestibility. Dried leaves of Daniellia oliveri were offered at two levels (25% and 50% of DMI) as supplement to a basal hay diet. A digestibility trial of 8 days was conducted after 10 days of adaptation period. Rumen liquor was sampled one hour before, and one, three and five hours after the morning feeding for three consecutive days. Diet D50% showed a higher (P<0.05) pH than both the control and D25% diets, respectively. Diet D25% had an inferior (P<0.05) pH than the controls. The ruminal ammonia concentration of D25% was superior (P<0.05) to D50% and the controls, respectively. Similarly, diet D50% had a superior (P<0.05) ruminal ammonia concentration than the controls. There were significant increases (P<0.05) in the OM, CP, NDF, ADF, ADL and cellulose intake of D50% diet compared with the controls. Similarly, inclusion level of 50% Daniellia oliveri resulted in a reduction (P<0.05) in digestibility of DMI, OM, NDF, ADF and ADL, in comparison to sheep fed the control diet. Cellulose and hemi-cellulose digestibility of diet D50% was superior (P<0.05) to that of the controls. It would appear that condensed tannins had inhibitory effect on organic matter and detergent fibre digestibility. It was concluded that Daniellia oliveri with a high CP and GE (165 g/kg and 20.3 kJ/g DM) respectively, could serve as a fodder tree for small ruminant in spite of its relatively high content of condensed tannin (48 g/kg DM). An inclusion range of 25 to 50% was recommended during period of scarcity.

Diversity of the gut microbiome in three grasshopper species using 16S rRNA and determination of cellulose digestibility

Background Grasshoppers are typical phytophagous pests, and they have large appetites with high utilization of plants fibers, the digestion of which may depend on the microorganisms in their intestines. Grasshoppers have the potential to be utilized in bioreactors, which could improve straw utilization efficiency in the future. In this study, we describe the gut microbiome in three species of grasshoppers, Oedaleus decorus asiaticus, Aiolopus tamulus and Shirakiacris shirakii, by constructing a 16S rDNA gene library and analyzed the digestibility of cellulose and hemicellulose in the grasshoppers by using moss black phenol colorimetry and anthrone colorimetry. Results There were 509,436 bacterial OTUs (Operational Taxonomic Units) detected in the guts of all the grasshoppers sampled. Among them, Proteobacteria and Firmicutes were the most common, Aiolopus tamulus had the highest bacterial diversity, and Shirakiacris shirakii had the highest bacterial species richness. The intestinal microflora structure varied between the different species of grasshopper, with Aiolopus tamulus and Shirakiacris shirakii being the most similar. Meanwhile, the time at which grasshopper specimens were collected also led to changes in the intestinal microflora structure in the same species of grasshoppers. Klebsiella may form the core elements of the microflora in the grasshopper intestinal tract. The digestibility of cellulose/hemicellulose among the three species grasshoppers varied (38.01/24.99%, 43.95/17.21% and 44.12/47.62%). LEfSe analysis and Spearman correlation coefficients showed that the hemicellulosic digestibility of Shirakiacris shirakii was significantly higher than that of the other two species of grasshopper, which may be related to the presence of Pseudomonas, Stenotrophomonas, Glutamicibacter, Corynebacterium, and Brachybacterium in Shirakiacris shirakii intestinal tract. Conclusion The intestinal microbial communities of the three grasshoppers species are similar on phylum level, but the dominant genera of different species grasshoppers are different. The cellulose digestibility of the three species of grasshoppers is relatively high, which may be correlated with the presence of some gut microbiome. Increasing the understanding of the structure and function of the grasshopper intestinal microflora will facilitate further research and the utilization of intestinal microorganisms in the future.