Igor Šurina

Valorisation of softwood bark through extraction of utilizable chemicals. A review

Softwood bark is an important source for producing chemicals and materials as well as bioenergy. Extraction is regarded as a key technology for obtaining chemicals in general, and valorizing bark as a source of such chemicals in particular. In this paper, properties of 237 compounds identified in various studies dealing with extraction of softwood bark were described. Finally, some challenges and perspectives on the production of chemicals from bark are discussed.

Composition of fatty acids and tocopherols in peels, seeds and leaves of Sea buckthorn

Abstract Peels, seeds and leaves of the Sea buckthorn were extracted by methanol and chloroform and characterized in terms of the fatty acids (FA) and tocopherol composition. All morphological parts of Sea buckthorn contained these biologically active compounds useful in medicine, pharmacology, human nutrition and cosmetics. The highest amount of α-tocopherol was found in peels (1103 mg kg-1). The lowest content of α-tocopherol was found in leaves (659 mg kg-1). Delta-tocopherol was found in higher amount in peels 1757 mg kg-1. Seeds contained 95 mg kg-1 of delta-tocopherols. Gamma-tocopherol was found in seeds (459 mg kg-1), peels (188 mg kg-1) and in leaves (587 mg kg-1). β-tocopherol was present only in seeds (171 mg kg-1). Unsaturated fatty acids were dominant in all morphological parts of Sea buckthorn. The highest amounts of unsaturated fatty acids (92 rel. %) were determined in seeds. Dominant fatty acids of seeds were linoleic acid (37 %), α-linolenic acid (30 %) and vaccenic acid (20 %). Leaves were rich in α-linolenic acid (51 %). Dominant fatty acids of peels were oleic acid (16 %), palmitic acid (33 %) and palmitoleic acid (29 %).

Deep Eutectic Solvents as Medium for Pretreatment of Biomass

In the field of green chemistry is the study of new solvent systems the great challenge. Deep eutectic solvents (DESs) represent the principles of green chemistry. Currently are preferred these new types of chemicals suitable for the selective removal of extractives, lignin or polysaccharides from biomass. Biomass is selectively treated to the individual fractions, of which is possible with following purification to obtain products in higher yields and purity. In this work are describes various deep eutectic solvents, which can be used for pretreatment of biomass.

Antibacterial and antifungal activity of phytosterols and methyl dehydroabietate of Norway spruce bark extracts

The current study focuses on the analysis of in vitro biological activity of extract from bark of Norway spruce (Picea Abies), which can find potential application in food and cosmetic industry and pharmacology. Milled bark was subjected to Soxhlet extraction and supercritical fluid extraction to obtain two ethanol extracts. These extracts were further used to obtain their pre-extracts to n-hexane. It was investigated whether beta-sitosterol exhibits bacteriostatic activity necessary to observe antimicrobial and antifungal activity of methyl dehydroabiatate. This synergic effect and bacteriostatic activity of beta-sitosterol have not been previously reported. The greatest inhibition zone of n-hexane pre-extracts was confirmed in bacterium Pseudomonas aeruginosa (0,9 - 1,5 cm) and yeast Alternaria alternata (0,7 - 1,6 cm). It is novel, the antioxidant, antimicrobial and antifungal activity of spruce bark extracts assessed in terms of food and cosmetic fortification.

Stability of the Lignins and their Potential in Production of Bioplastics

Chemical industry includes a biobased materials (sector) in which some oil-derived plastics and chemicals are replaced by new or alternative products derived, at least partially, from biomass. One of these biobased products is here today - lignin, but to fulfil its societal potential it is necessary to improve their market share while making valuable contributions to climate change mitigation. Great source of lignin is by-product (waste) from paper making industry. Lignin isolated from black liquors has a big potential to be used as a component for new bioplastic compositions. Lignosulphonates and lignin are polydispersions of different large fragments from natural tree dimensional lignin present in the wood. The kraft lignin consists of large amount of sulphur which is bonded in functional groups. Content of lignin in black liquor is in range 30 - 45% what brings potential of its isolation. In this paper we characterised and precipitated lignin with two inorganic and one organic acid (nitric, hydrochloric and tartaric acid).