Publications by authors named "Richard A Kohn"

The health benefits of grass-fed beef are well documented. However, the rumen microbiome features in beef steers raised in a grass-fed regimen have yet to be identified. This study examined the rumen microbiome profile in the feeding regimes.

View Article and Find Full Text PDF

The ruminal microbiome rapidly converts plant biomass to short-chain fatty acids (SCFA) that nourish the ruminant animal host. Because of its high species diversity, functional redundancy, and ease of extraruminal cultivation, this mixed microbial community is a particularly accomplished practitioner of the carboxylate platform for producing fuels and chemical precursors. Unlike reactor microbiomes derived from anaerobic digesters or sediments, the ruminal community naturally produces high concentrations of SCFA, with only modest methane production owing to the absence of both proton-reducing acetogens and aceticlastic methanogens.

View Article and Find Full Text PDF

Fermentation of crops, waste biomass, or gases has been proposed as a means to produce desired chemicals and renewable fuels. The second law of thermodynamics has been shown to determine the net direction of metabolite flow in fermentation processes. In this article, we describe a process to isolate and direct the evolution of microorganisms that convert cellulosic biomass or gaseous CO2 and H2 to biofuels such as ethanol, 1-butanol, butane, or hexane (among others).

View Article and Find Full Text PDF

Decline in surf scoter (Melanitta perspicillata) waterfowl populations wintering in the Chesapeake Bay has been associated with changes in the availability of benthic bivalves. The Bay has become more eutrophic, causing changes in the benthos available to surf scoters. The subsequent decline in oyster beds (Crassostrea virginica) has reduced the hard substrate needed by the hooked mussel (Ischadium recurvum), one of the primary prey items for surf scoters, causing the surf scoter to switch to a more opportune species, the dwarf surfclam (Mulinia lateralis).

View Article and Find Full Text PDF

Pollution of waters resulting from phosphorus (P) runoff from agricultural land receiving long-term manure application is one of the most serious threats to water quality in many regions of the world. Of various approaches to alleviate the problem, reducing P surplus on animal farms through optimizing P intake and minimizing P excretion in manure offers a great opportunity. Here, we present a fecal P test method that has the potential to identify over-feeding of P in dairy cattle.

View Article and Find Full Text PDF

Amylase and calcium chelators, such as disodium ethylene diaminotetraacetate (EDTA), are used in analysis of neutral detergent fiber (NDF) to dissolve starch and pectin, respectively. However, these reagents may interfere with each other's activity. Six combinations of alpha-amylase and EDTA were examined for determining NDF values of beet pulp (Beta vulgaris), ground corn (Zea mays L.

View Article and Find Full Text PDF

Phosphorus (P) surplus on dairy farms, especially confined operations, contributes to P buildup in soils with increased potential for P loss to waters. One approach to reduce P surplus and improve water quality is to optimize P feeding and improve P balance on farms. Here we report how varying P concentrations in lactating cow diets affects the amount as well as the chemical forms and fraction distribution of P in fecal excretion, and the environmental implications of this effect.

View Article and Find Full Text PDF