Bioethanol Production from Renewable Raw Materials and Its Separation and Purification: A Review

Proizvodnja biogoriva iz obnovljivih sirovina privukla je pažnju znanstvenika jer može poslužiti za opskrbu energijom i alternativnim gorivima. Bioetanol je jedno od najzanimljivijih biogoriva zbog njegovog pozitivnog utjecaja na okoliš. Najčešće se proizvodi iz sirovina koje sadržavaju šećer i škrob. Međutim, razni izvori lignocelulozne biomase, kao što su poljoprivredni i šumski ostaci te zeljasti energetski usjevi, također mogu poslužiti kao sirovine za proizvodnju bioetanola, energije, topline i kemikalija s dodanom vrijednošću. Lignoceluloza je složena mješavina ugljikohidrata, koju treba učinkovito prethodno obraditi da bi se oslobodili biotransformacijski putevi u kojima enzimi proizvode fermentabilne šećere što nakon hidrolize fermentiraju u etanol. Unatoč tehničkim i ekonomskim poteškoćama, obnovljive lignocelulozne sirovine imaju nisku cijenu te ne utječu na hranu i prehrambeni lanac, čime potiču održivost. Za proizvodnju bioetanola iz obnovljivih sirovina razvijeni su različiti načini rada bioprocesora. Osim toga, intenzivno se razvijaju i alternativni postupci odvajanja i pročišćavanja bioetanola. Ovaj rad daje pregled novih trendova u proizvodnji bioetanola iz različitih obnovljivih sirovina, te postupaka njegovog odvajanja i pročišćavanja.Production of biofuels from renewable feedstocks has captured considerable scientific attention since they could be used to supply energy and alternative fuels. Bioethanol is one of the most interesting biofuels due to its positive impact on the environment. Currently, it is mostly produced from sugar- and starch-containing raw materials. However, various available types of lignocellulosic biomass such as agricultural and forestry residues, and herbaceous energy crops could serve as feedstocks for the production of bioethanol, energy, heat and value-added chemicals. Lignocellulose is a complex mixture of carbohydrates that needs an efficient pretreatment to make accessible pathways to enzymes for the production of fermentable sugars, which after hydrolysis are fermented into ethanol. Despite technical and economic difficulties, renewable lignocellulosic raw materials represent low-cost feedstocks that do not compete with the food and feed chain, thereby stimulating the sustainability. Different bioprocess operational modes were developed for bioethanol production from renewable raw materials. Furthermore, alternative bioethanol separation and purification processes have also been intensively developed. This paper deals with recent trends in the bioethanol production as a fuel from different renewable raw materials as well as with its separation and purification processes

Recent Trends in Biodiesel and Biogas Production

Biodizel i bioplin dva su vrlo važna izvora obnovljive energije širom svijeta, a posebice u zemljama EU. Biodizel se gotovo isključivo koristi kao transportno gorivo, dok se bioplin uglavnom koristi za proizvodnju električne energije i topline. Primjena sofisticiranijih tehnika pročišćavanja u proizvodnji čistog biometana iz bioplina omogućuje njegovo uvođenje u mrežu prirodnog plina i daljnju uporabu kao transportno gorivo. Dok se bioplin uglavnom proizvodi od otpadnih materijala (materijal s odlagališta otpada, gnojivo, talog zaostao pročišćavanjem otpadnih voda, poljoprivredni otpad), biodizel se u EU uglavnom dobiva iz repice ili drugih uljarica koje se koriste kao hrana, što dovodi u pitanje njihovu ulogu kao hrane ili goriva. Kako bi se ublažio ovaj problem, napravljeni su značajni napori u korištenju neprehrambenih sirovina za proizvodnju biodizela. To uključuje sve vrste otpadnih ulja i masti, no od nedavno se više pažnje posvećuje proizvodnji mikrobnih ulja uzgojem mikroorganizama koji mogu akumulirati velike količine lipida u biomasi. Obećavajući kandidati za mikrobnu proizvodnju lipida mogu se pronaći među različitim sojevima filamentoznih plijesni, kvasaca, bakterija i mikroalgi. Sirovine od interesa su i poljoprivredni otpad bogat ugljikohidratima te različite lignocelulozne sirovine, za čiju se uporabu još uvijek moraju riješiti neka tehnička pitanja. Također, u ovom su radu razmatrane metode izdvajanja i pročišćavanja biodizela i bioplina.Biodiesel and biogas are two very important sources of renewable energy worldwide, and particularly in the EU countries. While biodiesel is almost exclusively used as transportation fuel, biogas is mostly used for production of electricity and heat. The application of more sophisticated purification techniques in production of pure biomethane from biogas allows its delivery to natural gas grid and its subsequent use as transportation fuel. While biogas is produced mostly from waste materials (landfills, manure, sludge from wastewater treatment, agricultural waste), biodiesel in the EU is mostly produced from rapeseed or other oil crops that are used as food, which raises the ‘food or fuel’ concerns. To mitigate this problem, considerable efforts have been made to use non-food feedstock for biodiesel production. These include all kinds of waste oils and fats, but recently more attention has been devoted to production of microbial oils by cultivation of microorganisms that are able to accumulate high amounts of lipids in their biomass. Promising candidates for microbial lipid production can be found among different strains of filamentous fungi, yeast, bacteria and microalgae. Feedstocks of interest are agricultural waste rich in carbohydrates as well as different lignocellulosic raw materials where some technical issues have to be resolved. In this work, recovery and purification of biodiesel and biogas are also considered

Recent Trends in Biodiesel and Biogas Production

Biodizel i bioplin dva su vrlo važna izvora obnovljive energije širom svijeta, a posebice u zemljama EU. Biodizel se gotovo isključivo koristi kao transportno gorivo, dok se bioplin uglavnom koristi za proizvodnju električne energije i topline. Primjena sofisticiranijih tehnika pročišćavanja u proizvodnji čistog biometana iz bioplina omogućuje njegovo uvođenje u mrežu prirodnog plina i daljnju uporabu kao transportno gorivo. Dok se bioplin uglavnom proizvodi od otpadnih materijala (materijal s odlagališta otpada, gnojivo, talog zaostao pročišćavanjem otpadnih voda, poljoprivredni otpad), biodizel se u EU uglavnom dobiva iz repice ili drugih uljarica koje se koriste kao hrana, što dovodi u pitanje njihovu ulogu kao hrane ili goriva. Kako bi se ublažio ovaj problem, napravljeni su značajni napori u korištenju neprehrambenih sirovina za proizvodnju biodizela. To uključuje sve vrste otpadnih ulja i masti, no od nedavno se više pažnje posvećuje proizvodnji mikrobnih ulja uzgojem mikroorganizama koji mogu akumulirati velike količine lipida u biomasi. Obećavajući kandidati za mikrobnu proizvodnju lipida mogu se pronaći među različitim sojevima filamentoznih plijesni, kvasaca, bakterija i mikroalgi. Sirovine od interesa su i poljoprivredni otpad bogat ugljikohidratima te različite lignocelulozne sirovine, za čiju se uporabu još uvijek moraju riješiti neka tehnička pitanja. Također, u ovom su radu razmatrane metode izdvajanja i pročišćavanja biodizela i bioplina.Biodiesel and biogas are two very important sources of renewable energy worldwide, and particularly in the EU countries. While biodiesel is almost exclusively used as transportation fuel, biogas is mostly used for production of electricity and heat. The application of more sophisticated purification techniques in production of pure biomethane from biogas allows its delivery to natural gas grid and its subsequent use as transportation fuel. While biogas is produced mostly from waste materials (landfills, manure, sludge from wastewater treatment, agricultural waste), biodiesel in the EU is mostly produced from rapeseed or other oil crops that are used as food, which raises the ‘food or fuel’ concerns. To mitigate this problem, considerable efforts have been made to use non-food feedstock for biodiesel production. These include all kinds of waste oils and fats, but recently more attention has been devoted to production of microbial oils by cultivation of microorganisms that are able to accumulate high amounts of lipids in their biomass. Promising candidates for microbial lipid production can be found among different strains of filamentous fungi, yeast, bacteria and microalgae. Feedstocks of interest are agricultural waste rich in carbohydrates as well as different lignocellulosic raw materials where some technical issues have to be resolved. In this work, recovery and purification of biodiesel and biogas are also considered

Potential of Energy Willow Plantations for Biological Reclamation of Soils Polluted by 137Cs and Heavy Metals, and for Control of Nutrients Leaking into Water Systems

Willow is a low-maintenance crop that has potential for energy production and enhancing the local environment. The area of commercial plantations of willow in Europe is mostly concentrated in Sweden, with more than 20 000 ha. Willow trees are used not only for energy production, but also for reclamation of polluted soils because a plantation may grow for 20–25 years, with a three-year period of harvesting. Our research covers issues of reclamation of soils contaminated by radionuclides and heavy metals, and decreasing of eutrophication of water ecosystems with using willow plantations. The field studies of phytoremediation of soil contaminated by 137Cs by willow plants were conducted in eastern Belarus, in the area where agricultural activity was banned after Chernobyl disaster. This region is heavily polluted with 137Cs (from 185 to 555 kBq/m2) and heavy metals. The transferring factors of accumulated 137Cs and heavy metals from the soil to willow biomass were determined. The field experiments showed that willow does not accumulate actively Cd and Pb, but it accumulates Zn, Cu and Mn intensively. The potassium application decreases the accumulation of 137Cs in willow biomass and increases accumulation of Cu, Zn and Mn, but has no influence on accumulation of Cd and Pb. Our results confirmed that soils polluted with radionuclide and heavy metals could be used for willow cultivation as energy crop, if adequate management is applied. The different potential of the willow species concerning heavy metals accumulation was also established. The yield of willow biomass on polluted soils achieved 11.5–12.8 DMg ha–1 per year, depending on variety, that is competitive with the ordinary yield of willow on mineral fertile soils. Willow plantations also may be used for accumulations of nutrients like nitrogen and phosphorus in watersheds. It enables to decrease impact for water ecosystems and to control eutrophication

The Assessment of Cost of Biomass from Post-Mining Peaty Lands for Pellet Fabrication

Post-mining peaty lands were formed as a result of peat extraction on drainage wetlands areas. After peat extraction has finished, the biggest problem is to use these lands for other purposes. This type of soil is very heterogenic, poorly drained, with massive structure and poor contents of nutrients. Thus it is very problematic to grow traditional agricultural crops that have special requirements for soil fertility on those areas. The area of post-mining peaty lands in Belarus alone is about 200 000 hectares. One of the perspective directions of post-mining peaty land use is re-wetting and production of biomass for energy purposes. The goal of our research was to estimate cost of biomass of natural grass and willow wood from short rotation coppice (SRC) plantations which may be used as feedstock for pellet production. The dominant wetland species were common reed, cattail and sedges. SRC plantation was planted on degraded soils. The prime cost of biomass which was produced on the base of natural grass was from 10.4 euro per ton to 13.2 euro per ton, depending on technology. The prime cost of willow biomass was 24.1 euro per ton. Introduction of taxes will increase cost of biomass by approximately 60 %. The calculation of economic efficiency identified that biomass as a feedstock for pellet production on post-peat mining areas may be a profitable direction for peat factory function and providing the sustainable development of local communities. Additional profit may be obtained as a result of saving carbon quotas. The share of CO2 emissions from fossil fuel for grass biomass production is about 2 % from the total volume of CO2 during renewable biomass utilization for energy and for chips production from willow wood - 6 %. The diversification of biomass sources enables to use feedstock for a pellet line in the winter and spring which is in the heating season

Bioethanol Production from Renewable Raw Materials and Its Separation and Purification: A Review

Production of biofuels from renewable feedstocks has captured considerable scientific attention since they could be used to supply energy and alternative fuels. Bioethanol is one of the most interesting biofuels due to its positive impact on the environment. Currently, it is mostly produced from sugar- and starch-containing raw materials. However, various available types of lignocellulosic biomass such as agricultural and forestry residues, and herbaceous energy crops could serve as feedstocks for the production of bioethanol, energy, heat and value-added chemicals. Lignocellulose is a complex mixture of carbohydrates that needs an efficient pretreatment to make accessible pathways to enzymes for the production of fermentable sugars, which after hydrolysis are fermented into ethanol. Despite technical and economic difficulties, renewable lignocellulosic raw materials represent low-cost feedstocks that do not compete with the food and feed chain, thereby stimulating the sustainability. Different bioprocess operational modes were developed for bioethanol production from renewable raw materials. Furthermore, alternative bioethanol separation and purification processes have also been intensively developed. This paper deals with recent trends in the bioethanol production as a fuel from different renewable raw materials as well as with its separation and purification processes

Recent Trends in Biodiesel and Biogas Production

Biodiesel and biogas are two very important sources of renewable energy worldwide, and particularly in the EU countries. While biodiesel is almost exclusively used as transportation fuel, biogas is mostly used for production of electricity and heat. The application of more sophisticated purification techniques in production of pure biomethane from biogas allows its delivery to natural gas grid and its subsequent use as transportation fuel. While biogas is produced mostly from waste materials (landfills, manure, sludge from wastewater treatment, agricultural waste), biodiesel in the EU is mostly produced from rapeseed or other oil crops that are used as food, which raises the ‘food or fuel’ concerns. To mitigate this problem, considerable efforts have been made to use non-food feedstock for biodiesel production. These include all kinds of waste oils and fats, but recently more attention has been devoted to production of microbial oils by cultivation of microorganisms that are able to accumulate high amounts of lipids in their biomass. Promising candidates for microbial lipid production can be found among different strains of filamentous fungi, yeast, bacteria and microalgae. Feedstocks of interest are agricultural waste rich in carbohydrates as well as different lignocellulosic raw materials where some technical issues have to be resolved. In this work, recovery and purification of biodiesel and biogas are also considered