Bark of Siberian Conifers: Composition, Use, and Processing to Extract Tannin

The rational use of natural resources, including the creation of new and improvement of existing technologies in order to reduce the anthropogenic impact on the environment, is currently an important task. This review covers different methods of softwood bark processing. Bark is used for the production of heat-insulating plates, and also as filler in adhesives and composites. In agriculture, it is used as a mulch. Softwood bark is a valuable raw material for chemical processing. Extractive substances of the bark are of particular interest. Among them, phenolic compounds are very important, in particular of tannin nature, which are used as tanning agents in leather production. Bark is used for the isolation of substances with antibacterial activity for pharmaceutical and nutraceutical applications. Aqueous-alkaline solutions, in particular monoethanolamine, are used as an extracting agent. Currently, tannins have been applied into many different fields, including medicine, food, beverage, the manufacture of ink and adhesives, the dye and tanning industry, plastic resins, water purification, and surface coatings. Tanning extracts obtained as a result of extraction are refined by ultrafiltration. The obtained extracts are of high purity. The extraction residue, the so-called tan, is a promising raw material for obtaining a cellulosic product. In addition to the chemical conversion of tan, biotechnological processing is an alternative option. In the process of tan biodegradation by the microscopic Trichoderma fungus, a biological product trichodermin is obtained, which is used to protect plants from phytopathogens.

Potential of Anaerobic Digestion-derived Biosolids as an Organic Addendum in Horticultural Growing Media

Soilless horticultural growing media are composed of organic matter, coarse aggregates, nutrients, and a wetting agent. Sphagnum peat has been the standard organic addendum to soilles growing media. However, recent shortages, escalating costs, and its acidity make sphagnum peat a sometimes less-than-desirable material. Alternatives such as composted bark dust, coconut coir, composted manure, and crop by-products have been proposed as substitutes for sphagnum peat, but none are a suitable general alternative. Anaerobic digestion-derived biosolids (ADB) has the potential to become a complete or partial substitute for sphagnum peat. ADB is a cellulosic product similar in appearance to sphagnum peat and is a product from the anaerobic digestion of cattle manure for 14 to 25 days at temperatures between 104 °F. and 140 °F. Bacteria from the animal's rumen, present in the manure prior to anaerobic digestion, are used to breakdown excessive nutrients present in the manure. Following anaerobic digestion, the nutrient-rich liquid phase is removed to yield an odorless cellulosic fiber that is sterile, free of weeds, pests, and pathogens, as well as uniform and reproducible. The potential application of ADB to the horticulture industry, most specifically as an organic addendum to soilless media, is immense and will be discussed. Use of anaerobic digester-derived biosolids in horticultural growing media is a protected intellectual property and available for license through the WiSys Technology Foundation.