ABSTRACT
Agricultural nutrient management is an issue due to P loss from fields and water quality degradation. This is especially true in watersheds where a history of P application in excess of crop needs has resulted in elevated soil P (legacy P). As practices and policy are implemented in such watersheds to reduce P loss, information is needed on time required to draw down soil P and how much P loss can be reduced by drawdown. We used the Annual P Loss Estimator (APLE) model to simulate soil P drawdown in Maryland, and to estimate P loss at a statewide scale associated with different combinations of soil P and P transport. Simulated APLE soil P drawdown compared well with measured rates from three field sites, showing that APLE can reliably simulate P dynamics for Maryland soils. Statewide APLE simulations of average annual P loss from cropland (0.84 kg ha) also compared well with estimates from the Chesapeake Bay Model (0.87 kg ha). The APLE results suggest that it is realistic to expect that a concerted effort to reduce high P soils throughout the state can reduce P loss to the Chesapeake Bay by 40%. However, P loss reduction would be achieved gradually over several decades, since soil P drawdown is very slow. Combining soil P drawdown with aggressive conservation efforts to reduce P transport in erosion could achieve a 62% reduction in state-level P loss. This 62% reduction could be considered a maximum amount possible that is still compatible with modern agriculture.
Subject(s)
Phosphorus/analysis , Soil/chemistry , Water Quality , Agriculture , Bays , MarylandABSTRACT
To determine the possible alternative use of tobacco, the seeds representing seven Maryland tobacco cultivars were investigated for their phytochemical, antioxidant, and antiproliferative properties. Tobacco seed oils were extracted by the Soxhlet method, and analyzed for their yield, density, refractive index, fatty acid profiles, and tocopherol profile. The defatted flours were extracted in 50% acetone and 80% ethanol. The tobacco seed oil and flour extracts were analyzed for total phenolic contents (TPC) and scavenging capacities against peroxyl, hydroxyl and 2,2-diphenyl-1-picryhydrazyl (DPPH) radicals. The fatty acid compositions of phospholipids and the protein content of the flours were also analyzed. In addition, oil and flour extracts of varieties MD609 and MD609LA were evaluated for their antiproliferative effects on HT-29 human colon cancer cells. All of the tested extracts significantly inhibited HT-29 cell proliferation except that from MD609 oil. The data from this study suggest the potential alternative use of tobacco seeds in developing natural antioxidants and antiproliferative agents for improving human health.
Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Antioxidants/analysis , Nicotiana/chemistry , Plant Extracts/chemistry , Plant Oils/chemistry , Seeds/chemistry , Cell Proliferation/drug effects , Fatty Acids/analysis , Free Radical Scavengers/analysis , HT29 Cells , Humans , Maryland , Phenols/analysis , Plant Extracts/pharmacology , Tocopherols/analysisABSTRACT
Coenzyme Q10 (CoQ10), a potent antioxidative dietary supplement, was produced using a photosynthetic bacteria Rhodospirillum rubrum ATCC 25852 by submerged fermentation supplemented with tobacco biomass hydrolysate (TBH) in comparison with media supplemented with hydrolysates prepared with alfalfa (ABH) or spinach (SBH). Growth medium supplemented with 20% (v/v) TBH was found favorable with regard to cell density and CoQ10 concentration. The stimulation effects on cell growth (shortened lag phase, accelerated exponential growth, and elevated final cell concentration) and CoQ10 production (enhanced specific CoQ10 content per unit cell weight) could be attributed to the presence of solanesol, the precursor of CoQ10, in the tobacco biomass. The final yield of CoQ10 reached 20.16 mg/l in the fermentation medium supplemented with 20% TBH.
Subject(s)
Biomass , Nicotiana/metabolism , Photosynthesis , Rhodospirillum rubrum/metabolism , Ubiquinone/analogs & derivatives , Bioreactors , Fermentation , Ubiquinone/biosynthesisABSTRACT
Solanesol in the waste streams of a bioprocess designed for alternative applications of low-alkaloid tobacco was recovered using three different extraction methods. Compared to the conventional heat-reflux extraction (HRE) and ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) using 1:3 hexane:ethanol (v/v) as the solvent after saponification treatment of tobacco biomass was found the most effective in terms of solanesol yield, processing time, and volume of solvent consumed. Quantification of solanesol was achieved by optimizing the mobile phase at 60/40 acetonitrile-isopropanol and lowering the oven temperature to 22 degrees C using a standard reverse-phase high performance liquid chromatography (RP-HPLC). The total solanesol recovered from tobacco biomass and chloroplast accounted for 30% (w/w) of the total solanesol in the fresh leaves. Since solanesol is the precursor of metabolically active quinones such as coenzyme Q10 and vitamin K analogues, extraction of solanesol from tobacco bioprocess waste is a feasible operation and could leverage the overall profitability of biorefining tobacco for alternative, value-added uses.
