Volatile organic compounds (VOCs) and odors in cattle rumen gas have been characterized by in-vivo headspace sampling by solid-phase microextraction (SPME) and analysis by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A novel device enabling headspace SPME (HS-SPME) sampling through a cannula was designed, refined, and used to collect rumen gas samples from steers. A Carboxen-pol...

Considering the projected demand for protein supplementation in animal feed, as well prioritizing plant-based provision growing human population, great stress is imposed on conventional sources, calling new sustainable alternatives. In this regard, production and application of single-cell proteins (SCPs) has proven to be a promising alternative. Therefore, study, volatile fatty acids (VFAs) ef...

the effect of three levels (0, 28.65, 57.31mg /200mg substrate) of golpar (heracleum persicum: hp) on in vitro rumen ecosystem and on methane production was assessed. gas production (gp) was recorded from 1 to 54h past of incubation. the parameters studied were in vitro gas production (ivgp), methane production, ammonia-n concentration (nh3-n), in vitro organic matter degradability (ivomde), pa...

For many years, analysis of short chain fatty acids (volatile fatty acids, VFAs) has been routinely used in identification of anaerobic bacteria. In numerous scientific papers, the fatty acids between 9 and 20 carbons in length have also been used to characterize genera and species of bacteria, especially nonfermentative Gram negative organisms. With the advent of fused silica capillary columns...

A batch anaerobic test was conducted to evaluate the effects of inoculum/substrate ratios (ISRs) on the methane yield and orthophosphate release from the anaerobic digestion of Microcystis spp. The results demonstrated an obvious influence on methane yield and orthophosphate release by ISR. The maximum methane yield decreased from 140.48 to 94.42 mL/gVS when the ISR decreased from 2.0 to 0.5. T...

For many years, analysis of short chain fatty acids (volatile fatty acids, VFAs) has been routinely used in identification of anaerobic bacteria. In numerous scientific papers, the fatty acids between 9 and 20 carbons in length have also been used to characterize genera and species of bacteria, especially nonfermentative Gram negative organisms. With the advent of fused silica capillary columns...

The looming climate and energy crises, exacerbated by increased waste generation, are driving research development of sustainable resource management systems. Research suggests that organic materials, such as food waste, grass, manure, have potential for biotransformation into a range products, including: high-value volatile fatty acids (VFAs); various carboxylic acids; bioenergy; bioplastics. ...

A laboratory-scale acidogenic anaerobic sequencing batch reactor was set up to test the effect of pH change on microbial community structure of the reactor biomass and process performance. No immediate performance change on acidogenesis was observed after the pH change. However, as the hydrogenotrophic methanogen population decreased, hydrogen content in biogas increased followed by a sharp dec...

Approximate linear programs (ALPs) are well-known models for computing value function approximations (VFAs) for high dimensional Markov decision processes (MDPs) arising in business applications. VFAs from ALPs have desirable theoretical properties, define an operating policy, and provide a lower bound on the optimal policy cost, which can be used to assess the suboptimality of heuristic polici...