Impact of effective microbes (em) bokashi supplementation on nutrients digestibility, rumen fermentation and gas volume production in diets of sheep

The present study was conducted to determine the appropriate type of by-products {sugar beet pulp (SBP), grape seeds (GS), olive cake (OC), citrus pulp (CtP), and jojoba meal (JM)} fermented with activated effective microorganisms (EM-Bokashi) to be integrated into the diet of sheep to obtain the best nutrient digestibility and rumen characteristic of Barki sheep. An in vitro experiment was carried out on five fistulated females for rumen fermentation activity, while 15 males were used for digestibility trials. Treatment with EM caused less cell wall content. GS and CtP had higher feed intake (FI) and digestibility coefficients; the lower was found for JM as well less FI. SBP and JM had a higher pH and NH3 concentration, while they were less for GS and CtP. Those had higher total volatile fatty acids (TVFA's) concentration, percentage of acetate, and acetic to propionic (A/P) ratio. JM had less acetate, A/P and higher propionate and butyrate. Higher gas volume after 24h fermentation was noticed for GS and CtP, they were higher kinetic parameters as well, but they were less methane production and more ME (MJ/kg DM), OMD (%) and microbial protein syntheses. Therefore, in conclusion, feeding Bokashi of GS or CtP to sheep can improve productivity, while using Bokashi of JM should be combined with other feeds.

Optimization of extracellular ethanol-tolerant β-glucosidase production from a newly isolated Aspergillus sp. DHE7 via solid state fermentation using jojoba meal as substrate: purification and biochemical characterization for biofuel preparation

Background The increasing demand and the continuous depletion in fossil fuels have persuaded researchers to investigate new sources of renewable energy. Bioethanol produced from cellulose could be a cost-effective and a viable alternative to petroleum. It is worth note that β-glucosidase plays a key role in the hydrolysis of cellulose and therefore in the production of bioethanol. This study aims to investigate a simple and standardized method for maximization of extracellular β-glucosidase production from a novel fungal isolate under solid-state fermentation using agro-industrial residues as the sole source of carbon and nitrogen. Furthermore, purification and characterization of β-glucosidase were performed to determine the conditions under which the enzyme displayed the highest performance. Results A fungus identified genetically as a new Aspergillus sp. DHE7 was found to exhibit the highest extracellular β-glucosidase production among the sixty fungal isolates tested. Optimization of culture conditions improved the enzyme biosynthesis by 2.1-fold (174.6 ± 5.8 U/g of dry substrate) when the fungus grown for 72 h at 35 °C on jojoba meal with 60% of initial substrate moisture, pH 6.0, and an inoculum size of 2.54 × 107 spores/mL. The enzyme was purified to homogeneity through a multi-step purification process. The purified β-glucosidase is monomeric with a molecular mass of 135 kDa as revealed by the SDS-PAGE analysis. Optimum activity was observed at 60 °C and pH of 6.0, with a remarkable pH and thermal stability. The enzyme retained about 79% and 53% of its activity, after 1 h at 70 °C and 80 °C, respectively. The purified β-glucosidase hydrolysed a wide range of substrates but displaying its greater activity on p-nitrophenyl-β-D-glucopyranoside and cellobiose. The values of Km and Vmax on p-nitrophenyl β-D-glucopyranoside were 0.4 mM and 232.6 U/mL, respectively. Purified β-glucosidase displayed high catalytic activity (improved by 25%) in solutions contained ethanol up to 15%. Conclusion β-glucosidase characteristics associated with its ability to hydrolyse cellobiose, underscore its utilization in improving the quality of food and beverages. In addition, taking into consideration that the final concentration of ethanol produced by the conventional methods is about 10%, suggests its use in ethanol-containing industrial processes and in the saccharification processes for bioethanol production. Graphical abstract