Abstract. Marine macroalgae (seaweed) conventionally has been used for environmental and commercial purposes; recently a growing interest has been focused also on seaweed detritus as a sustainable/cost-efficient feedstock for biogas (biomethane) anaerobic production. A wide set of factors influence the yield of biogasnevertheless, the recent paper emphasizes pretreatment of processed algal material (substrate) with winemaking waste (inoculum) as a particularly promising project for biogas production. Relevant pilot study carried out at the Liepaja University clearly demonstrates advantages of such a combination (i.e. co-fermentation of mixed substances) for biofuel feedstock design: winemaking waste considerably increases biogas (biomethane) output from seaweed substrate. Still, the results of these preliminary experiments have to be supported by further research.Keywords: processed seaweeds, winemaking waste, anaerobic digestion, biogas, substrate-inoculum. IntroductionRapid growth of energy consumption escalates global community's dependence on nonrenewable fossil fuel (which supplies about 80 % of the world's energy needs [1]) making it more and more urgent to search for alternative, more secure energy sources.Recently different energy types have been appraised and are already in use to replace fossil fuels -e.g. wind, solar, geothermal, tidal, nuclear, hydroelectric, biofuel, etc. energy. However, these alternative energy resources often possess specific disadvantages, like costliness, dependence on environmental conditions, damage to ecosystems, a lot of space needed (for discussion see, e.g. [2]) -consequently, viability considerations are of particular importance, when deciding about alternative energy projects.Bearing in mind this viability/sustainability approach the authors of the present paper are focusing on easy-to-access organic waste materials (namely, macroalgae detritus enhanced by winemaking waste inoculum) derived biogas as a particularly promising option within the spectrum of fossil fuel substitutions. Liepaja District (Baltic Sea coastal area in Western Latvia) has been used as a research site, where algae raw biomaterial has been collected and seaweed biofuels related experiments carried out.

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This paper presents the main results from a set of guidelines on the physico-mathematical modelling of laser surface-treatment of wear-resistant implants for human joint replacements. These guidelines contain synthesized and documented procedure, theoretical and practical recommendations, which are provided by researchers in the Nanomaterials Laboratory under the Institute of Fundamental Science and Innovative Technologies, Liepaja University. The present paper does not attempt to cover all aspects of physical and mathematical modelling, but draws together many key aspects concerning theoretical and practical difficulties, in the overcoming of what researchers of the Nanomaterials Laboratory, in particular, the authors of the present paper, have sufficient skills.

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Since worldwide distribution of non-degradable plastic waste causes serious environmental pollution, growing efforts have been made to replace traditional petroleum derived plastics with biological ones. The present paper focuses on seaweed (macroalgae) detritus as a potential feedstock for bioplastic production, since significant quantities of seaweed residues are available in the research site -Kurzeme coast (Western Latvia). This study aims to adapt the method for polylactic acid (PLA) plastics manufacturing from red seaweed Furcellaria lumbricalis (black carrageen) and to manipulate properties of the plastic material produced. Furcellaria material has been gathered on Kurzeme coast in Liepaja city and brought to the Liepaja University for carrageenan substances isolation/separation. The samples were thoroughly washed with tap water, then boiled for 2 hours and hot filtered into cold isopropanol and subsequently blended with plasticizers (glycerine, potato starch, seaweed particles) in order to achieve the desirable physical and thermomechanical properties of the carrageenan product. At the end, the samples were dried at temperature 25 ºC for 24 hours. Carrageenan material was improved through combining two plasticizers (potato starch and glycerine)bioplastic was suitable now for manufacturing spoons, cups, packaging boxes, etc. Still, research results should be considered as preliminary onesfurther studies are necessary to develop compatible bioplastic from Furcellaria.