Obtaining Multiple Coproducts from Red Grape Pomace via Anthocyanin Extraction and Biogas Production.

Red grape pomace (RGP), a byproduct of red wine production, is an abundant food processing waste stream in California, rich in both anthocyanins, a class of red-blue pigments, and lignocellulose. Extraction of anthocyanins and biofuel production from RGP have been investigated independently, but no research has examined employing both strategies together for maximal valorization. In this study, anthocyanins were most effectively extracted from RGP at 80 °C. Convection- and vacuum-oven drying of the pomace were found to decrease anthocyanin yield, whereas lyophilization did not significantly affect yield. Fermentable sugars were successfully separated from the crude extract via solid-phase extraction. Ionic liquid pretreatment of RGP was determined to be a nonviable option for application to anaerobic digestion. Extraction reduced biomethane output, but supplementation with the aqueous fraction of the extract mitigated much of this difference, indicating sequential extraction and fractionation of anthocyanins from RGP can minimize the impact on biofuel yields.

Immunomodulatory and Antibacterial Properties of the Chumash Medicinal Plant Trichostema lanatum.

Background: The woody shrub Trichostema lanatum Benth. (Lamiaceae) is native to Southern California and was reportedly used by the Chumash people as a disinfectant and for the treatment of rheumatism. Based on its traditional uses, this study investigated the antibacterial and immunomodulatory properties of extracts from T. lanatum.Methods: A methanolic extract of the leaves and stems of T. lanatum was tested for immunomodulatory activity by measuring the proliferation of murine macrophage cell cultures and the production of the pro-inflammatory cytokine TNF-α by the cells after treatment with T. lanatum. Antibacterial activity of the extract against a panel of six Gram-positive bacteria and two Gram-negative bacteria was evaluated using a disc-diffusion assay. Results: The T. lanatum extract inhibited the growth of Gram-positive bacteria, but not Gram-negative bacteria. Treatment of activated macrophage cell cultures with T. lanatum extract resulted in decreased proliferation of the activated macrophages and a decrease in the production of TNF-α. Conclusions: These results provide the first pharmacological support for the traditional use of T. lanatum by the Chumash people of Southern California as a disinfectant and treatment for rheumatism.

Antibacterial activity of fractions from three Chumash medicinal plant extracts and in vitro inhibition of the enzyme enoyl reductase by the flavonoid jaceosidin.

We have investigated the in vitro antibacterial bioactivity of dichloromethane-soluble fractions of Artemisia californica, Trichostema lanatum, Salvia apiana, Sambucus nigra ssp. cerulea and Quercus agrifolia Née against a ΔtolC mutant strain of Escherichia coli. These plants are traditional medicinal plants of the Chumash American Indians of Southern California. Bioassay-guided fractionation led to the isolation of three flavonoid compounds from A. californica: jaceosidin (1), jaceidin (2), and chrysoplenol B (3). Compounds 1 and 2 exhibited antibacterial activity against E. coli ΔtolC in liquid cultures. The in vitro activity of 1 against the enoyl reductase enzyme (FabI) was measured using a spectrophotometric assay and found to completely inhibit FabI activity at a concentration of 100 µM. However, comparison of minimum inhibitory concentration values for 1-3 against E. coli ΔtolC and an equivalent strain containing a plasmid constitutively expressing fabI did not reveal any selectivity for FabI in vivo.

The Effect of Ionic Liquid Pretreatment on the Bioconversion of Tomato Processing Waste to Fermentable Sugars and Biogas.

Tomato pomace is an abundant lignocellulosic waste stream from industrial tomato processing and therefore a potential feedstock for production of renewable biofuels. However, little research has been conducted to determine if pretreatment can enhance release of fermentable sugars from tomato pomace. Ionic liquids (ILs) are an emerging pretreatment technology for lignocellulosic biomass to increase enzymatic digestibility and biofuel yield while utilizing recyclable chemicals with low toxicity. In this study, pretreatment of tomato pomace with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) was investigated. Changes in pomace enzymatic digestibility were affected by pretreatment time and temperature. Certain pretreatment conditions significantly improved reducing sugar yield and hydrolysis time compared to untreated pomace. Compositional analyses suggested that pretreatment primarily removed water-soluble compounds and enriched for lignocellulose in pomace, with only subtle changes to the composition of the lignocellulose. While tomato pomace was effectively pretreated with [C2mim][OAc] to improve enzymatic digestibility, as of yet, unknown factors in the pomace caused ionic liquid pretreatment to negatively affect anaerobic digestion of pretreated material. This result, which is unique compared to similar studies on IL pretreatment of grasses and woody biomass, highlights the need for additional research to determine how the unique chemical composition of tomato pomace and other lignocellulosic fruit residues may interact with ionic liquids to generate inhibitors for downstream fermentation to biofuels.