Crude fucoidan content in two North Atlantic kelp species, Saccharina latissima and Laminaria digitata-seasonal variation and impact of environmental factors.

Fucoidans are sulphated fucose-rich polysaccharides predominantly found in the cell walls of brown algae. The bioactive properties of fucoidans attract increasing interest from the medico-pharmaceutical industries and may drive an increase in demand of brown algae biomass. In nature, the biochemical composition of brown algae displays a seasonal fluctuation driven by environmental factors and endogenous rhythms. To cultivate and harvest kelps with high yields of fucoidans, knowledge is needed on seasonal variation and impact of environmental conditions on the fucoidan content of brown algae. The relations between the fucoidan content and key environmental factors (irradiance, nutrient availability, salinity and exposure) were examined by sampling natural populations of the common North Atlantic kelps, Saccharina latissima and Laminaria digitata, over a full year at Hanstholm in the North Sea and Aarhus in the Kattegat. In addition, laboratory experiments were carried out isolating the effects of the single factors. The results demonstrated that (1) seasonal variation alters the fucoidan content by a factor of 2-2.6; (2) interspecific differences exist in the concentrations of crude fucoidan (% of dry matter): L. digitata (11%) > S. latissima (6%); and (3) the effects of single environmental factors were not consistent between species or between different conspecific populations. The ambiguous response to single environmental factors complicates prospective directions for manipulating an increased content of fucoidan in a cultivation scenario and emphasizes the need for knowledge on performance of local kelp ecotypes.

Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative.

Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO), an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi© plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material.

Butanol fermentation of the brown seaweed Laminaria digitata by Clostridium beijerinckii DSM-6422.

Seaweed represents an abundant, renewable, and fast-growing biomass resource for 3rd generation biofuel production. This study reports an efficient butanol fermentation process carried out by Clostridium beijerinckii DSM-6422 using enzymatic hydrolysate of the sugar-rich brown seaweed Laminaria digitata harvested from the coast of the Danish North Sea as substrate. The highest butanol yield (0.42g/g-consumed-substrates) compared to literature was achieved, with a significantly higher butanol:acetone-butanol-ethanol (ABE) molar ratio (0.85) than typical (0.6). This demonstrates the possibility of using the seaweed L. digitata as a potential biomass for butanol production. For the first time, consumption of alginate components was observed by C. beijerinckii DSM-6422. The efficient utilization of sugars and lactic acid further highlighted the potential of using this strain for future development of large-scale cost-effective butanol production based on (ensiled) seaweed.

Protein enrichment of cassava residue using Trichoderma pseudokoningii (ATCC 26801).

Solid state fermentation of cassava residue with Trichoderma pseudokoningii was conducted for 12 days. The fermentation was carried out at temperature of 24 °C and a pH of 5.0. Urea and ammonium sulphate were used as nutrient sources and moisture content varied at 60 and 70 %. Protein content of the unfermented cassava residue was increased from 8.4 to 12.5 % when urea was used with initial moisture content of 70 % w/v. This study showed that a maximum of 48.1 % protein enrichment was achieved using urea as a source of nutrient for the growth of the fungi, whiles ammonium sulphate achieved 36.9 % protein enrichment under the same condition.

Integrated bioethanol and protein production from brown seaweed Laminaria digitata.

A wild-growing glucose-rich (i.e. 56.7% glucose content) brown seaweed species Laminaria digitata, collected from the North Coast of Denmark in August 2012, was used as the feedstock for an integrated bioethanol and protein production. Glutamic acid and aspartic acid are the two most abundant amino acids in the algal protein, both with proportional content of 10% in crude protein. Only minor pretreatment of milling was used on the biomass to facilitate the subsequent enzymatic hydrolysis and fermentation. The Separate Hydrolysis and Fermentation (SHF) resulted in obviously higher ethanol yield than the Simultaneous Saccharification and Fermentation (SSF). High conversion rate at maximum of 84.1% glucose recovery by enzymatic hydrolysis and overall ethanol yield at maximum of 77.7% theoretical were achieved. Protein content in the solid residues after fermentation was enriched by 2.7 fold, with similar distributions of amino acids, due to the hydrolysis of polymers in the seaweed cell wall matrix.

Optimisation of enzymatic hydrolysis of cassava peel to produce fermentable sugars.

Enzymatic hydrolysis of cassava peels was evaluated using cellulase and beta-glucanase enzymes and their mixtures at three different enzyme loadings with time. The pH of the medium used for hydrolysis was 5 and the temperature was 50 °C. The efficiency of the hydrolysis using beta-glucanase was better than cellulase and glucose recovery of 69 % was realised when beta-glucanase dosage was increased to 10 % (v/w) at 48 h which rose to 73 % at 120 h, releasing 11.19 g/l and 12.17 g/l of glucose respectively. Less than 20 % of glucose was hydrolysed at 10 % (v/w) cellulase at 120 h releasing 2.6 g/l glucose. The optimum experimental condition for hydrolysis of cassava peel was established at 120 h when glucose recovery increased to 88 % for enzyme mixture of 5 % (v/w) cellulase + 10 % (v/w) beta-glucanase producing 14.67 g/l glucose in the hydrolysate.

Pretreatment of the macroalgae Chaetomorpha linum for the production of bioethanol--comparison of five pretreatment technologies.

A qualified estimate for pretreatment of the macroalgae Chaetomorpha linum for ethanol production was given, based on the experience of pretreatment of land-based biomass. C. linum was subjected to hydrothermal pretreatment (HTT), wet oxidation (WO), steam explosion (STEX), plasma-assisted pretreatment (PAP) and ball milling (BM), to determine effects of the pretreatment methods on the conversion of C. linum into ethanol by simultaneous saccharification and fermentation (SSF). WO and BM showed the highest ethanol yield of 44 g ethanol/100g glucan, which was close to the theoretical ethanol yield of 57 g ethanol/100g glucan. A 64% higher ethanol yield, based on raw material, was reached after pretreatment with WO and BM compared with unpretreated C. linum, however 50% of the biomass was lost during WO. Results indicated that the right combination of pretreatment and marine macroalgae, containing high amounts of glucan and cleaned from salts, enhanced the ethanol yield significantly.

Examining the potential of plasma-assisted pretreated wheat straw for enzyme production by Trichoderma reesei.

Plasma-assisted pretreated wheat straw was investigated for cellulase and xylanase production by Trichoderma reesei fermentation. Fermentations were conducted with media containing washed and unwashed plasma-assisted pretreated wheat straw as carbon source which was sterilized by autoclavation. To account for any effects of autoclavation, a comparison was made with unsterilized media containing antibiotics. It was found that unsterilized washed plasma-assisted pretreated wheat straw (which contained antibiotics) was best suited for the production of xylanases (110 IU ml(-1)) and cellulases (0.5 filter paper units (FPU) ml(-1)). Addition of Avicel boosted enzyme titers with the highest cellulase titers (1.5 FPU ml(-1)) found with addition of 50 % w/w Avicel and with the highest xylanase production (350 IU ml(-1)) reached in the presence of 10 % w/w Avicel. Comparison with enzyme titers from other nonrefined feedstocks suggests that plasma pretreated wheat straw is a promising and suitable substrate for cellulase and hemicellulase production.