Potential bioethanol and biogas production using lignocellulosic biomass from winter rye, oilseed rape and faba bean

To meet the increasing need for bioenergy several raw materials have to be considered for the production of e.g. bioethanol and biogas.In this study, three lignocellulosic raw materials were studied, i.e. (1) winter rye straw (Secale cereale L), (2) oilseed rape straw (Brassica napus L.) and (3) faba bean straw (Viciafaba L.). Their composition with regard to cellulose, hemicellulose, lignin, extractives and ash was evaluated, as well as their potential as raw materials for ethanol and biogas production. The materials were pretreated by wet oxidation using parameters previously found to be optimal for pretreatment of corn stover (195 1C, 15 min, 2 g l_1 Na2CO3 and 12 bar oxygen). It was shown that pretreatment was necessary for ethanol production from all raw materials and gave increased biogas yield from winter rye straw. Neither biogas productivity nor yield from oilseed rape straw or faba bean straw was significantly affected by pretreatment. Ethanol was produced by the yeast Saccharomyces cerevisiae during simultaneous enzymatic hydrolysis of the solid material after wet oxidation with yields of 66%, 70% and 52% of theoretical for winter rye, oilseed rape and faba bean straw, respectively. Methane was produced with yields of 0.36, 0.42 and 0.44 l g_1 volatile solids for winter rye, oilseed rape and faba bean straw, respectively, without pretreatment of the materials. However, biogas productivity was low and it took over 50 days to reach the final yield. It could be concluded that all three materials are possible raw materials for either biogas or ethanol production; however, improvement of biogas productivity or ethanol yield is necessary before an economical process can be achieved. 2007 Elsevier Ltd. All rights reserved

Why diversify annual biomass production for energy – exemplified by green house gas emissions from the Danish IBUS bioethanol production concept

There is a need for integrating the biomass starting point into the energy manufacturing steps. It will secure that bioenergy is produced with limited use of non-renewable fossil fuel to secure that in the application of biomass a net emission reduction of green house gasses take place along the whole chain. Intercropping, defined as the cultivation of two or more species simultaneously on the same area of land, is an traditional practice still widespread in the tropics and common in developed countries before the ‘fossilization’ of agriculture. This cropping strategy is based on the manipulation of plant interactions in time and space to optimize resource use and productivity. It is regarded as the practical application of basic ecological principles such as diversity, competition and facilitation (Hauggaard-Nielsen et al., 2007). Cereal-legume annual intercropping show the possibility to increase input of leguminous symbiotic nitrogen (N) fixation into cropping systems reducing the need for fertilizer N applications (Jensen, 1996). Moreover, less need for pesticides are obtained due to improved competition towards weeds (Hauggaard-Nielsen et al., 2001) and less general damages on intercropped species by pest and disease organisms (Hauggaard-Nielsen et al., 2007). Intercropping is a more adaptive management practice as compared to the present arable crop rotations consisting mainly of sole crops. Perennials like clover-grass intercrops or mixtures are obviously more diversified than traditional annual crops. Clover-grass leys are important in many agroecosystems today due to quality as feed for livestock, a high dry matter production (10 t ha-1 yr-1 unfertilized, where 95% of the N accumulation is N2 fixed by clover (Jørgensen et al., 1999) providing a nitrogen-rich residue, which may significantly reduce fertilizer requirements for the succeeding crop when mineralized (Hauggaard-Nielsen et al., 1998). Furthermore, clover-grass lays can be harvested several times a year and processed to ethanol throughout the year. It is very much questioned whether bioethanol is a sustainable energy resource that can offer environmental and long-term economic advantages over fossil fuels, like gasoline or diesel. The aim of the present presentation is to debate the substitution of fossil fuels by crop biomass requiring the right selection of plant species according not only to chemical quality for efficient conversion but also to secure the development of ecologically benign farming system including biomass for energy

Extraction and Quantification of Chlorophylls, Carotenoids, Phenolic Compounds, and Vitamins from Halophyte Biomasses

Halophytes are salt-tolerant plants, and they have been utilised as healthy, nutritious vegetables and medicinal herbs. Various studies have shown halophytes to be rich in health-beneficial compounds with antioxidant activity, anti-inflammatory and antimicrobial effects, and cytotoxic properties. Despite their potential, these plants are still underutilised in agriculture and industrial applications. This review includes the state-of-the-art literature concerning the contents of proanthocyanidins (also known as condensed tannins), total phenolic compounds, photosynthetic pigments (chlorophyll and carotenoids), and vitamins in various halophyte biomasses. Various extraction and analytical methods are also considered. The study shows that various species have exhibited potential for use not only as novel food products but also in the production of nutraceuticals and as ingredients for cosmetics and pharmaceuticals

Evaluation of marine Synechococcus for an algal biorefinery in arid regions

Implementing microalgae biorefinery in arid environments requires utilization of strains that can grow at high temperatures (above 28 °C) and salinity levels (above 30 ppt). In this study, we investigate the newly isolated seawater strain, Synechococcus, native to the United Arab Emirates, and evaluate its value as a perspective organism for cultivation (for fuel and bio-products) in regions with freshwater scarcity. The strain displayed tolerance to a wide range of temperature (22–37 °C) and salinity (20–41 ppt), with maximum biomass concentration of 0.72 g L−1 and a maximum growth rate of 82 mg L−1 d−1 at 25 °C and 33 ppt salinity. Lipids accumulation reached up to 26% of dry weight in nitrogen-depleted conditions (with 1.8 mM of nitrates addition to the media), whereas protein content exceeded 50% dry weight. In this study, harvesting is investigated using three chemical agents: Ferric chloride, sodium hydroxide, and chitosan. Cell disruption is analyzed for four distinct treatments: Enzymatic, alkaline, ultrasonic, and hydrothermal. Among tested methods, flocculation with sodium hydroxide and ultrasonication were found to be the most efficient techniques for harvesting and cell disruption, respectively. The growth characteristics of the local strain and the potential to derive protein and lipids from it makes it a promising biomass in a biorefinery context