Segmented two-dimensional liquid chromatography. Proof of concept study.

The separation in liquid chromatography is defined either by the space domain where it proceeds until the least retained analyte reaches the outlet of the column or by the time when individual analytes elute out of the column. These two approaches lead to the four possible combinations of two-dimensional liquid chromatography with online space x time coupling being the least experimentally feasible. Here, we show the development of a novel two-dimensional liquid chromatography method combining separation defined by space and the conventional elution-based separation. First-dimension column consisted of four capillary segments coupled serially via two-position six-port valves allowing an online and comprehensive transfer of analytes from the first to the second dimension. After initial experiments using homemade monolithic capillary columns, we tested commercially available columns in both dimensions. We ended with the combination of packed capillary columns in the first dimension and monolithic capillary column in the second dimension. We used a reversed-phase retention mechanism in the first spatial dimension, while HILIC was in the second, time-based dimension. We also developed a theoretical model to describe the proposed two-dimensional separation that was further confirmed by utilizing both an isocratic and gradient elution in the second dimension. Finally, we applied our experimental setup to separate neurotransmitters contained in human urine.

Organosolv Fractionation of Birch Sawdust: Establishing a Lignin-First Biorefinery.

The use of residual biomass for bioconversions makes it possible to decrease the output of fossil-based chemicals and pursue a greener economy. While the use of lignocellulosic material as sustainable feedstock has been tried at pilot scale, industrial production is not yet economically feasible, requiring further technology and feedstock optimization. The aim of this study was to examine the feasibility of replacing woodchips with residual sawdust in biorefinery applications. Woodchips can be used in value-added processes such as paper pulp production, whereas sawdust is currently used mainly for combustion. The main advantages of sawdust are its large supply and a particle size sufficiently small for the pretreatment process. Whereas, the main challenge is the higher complexity of the lignocellulosic biomass, as it can contain small amounts of bark and cambium. Here, we studied the fractionation of birch sawdust by organosolv pretreatment at two different temperatures and for two different durations. We evaluated the efficiency of fractionation into the three main fractions: lignin, cellulose, and hemicellulose. The cellulose content in pretreated biomass was as high as 69.2%, which was nearly double the amount in untreated biomass. The obtained lignin was of high purity, with a maximum 4.5% of contaminating sugars. Subsequent evaluation of the susceptibility of pretreated solids to enzymatic saccharification revealed glucose yields ranging from 75% to 90% after 48 h but reaching 100.0% under the best conditions. In summary, birch sawdust can be successfully utilized as a feedstock for organosolv fractionation and replace woodchips to simplify and lower the costs of biorefinery processes.

Organosolv fractionation of spruce bark using ethanol-water mixtures: Towards a novel bio-refinery concept.

The aim of this study was to assess the effect of hot water extraction followed by organosolv pretreatment on the enzymatic hydrolysability of spruce bark biomass. To this end, samples were pretreated at five different temperatures in the presence or not of acid catalyst. The cellulose content of pretreated biomass reached 49.6% w/w. During the enzymatic hydrolysis trials with 3% w/w dry solids, the final hydrolysis yield reached up to 70.1%, which corresponded to the release of 7.8 g/L of glucose. Whereas, the final hydrolysis yield obtained during the high-gravity enzymatic hydrolysis reached up to 43.5%. The concentration of released glucose was in range of 33.3 - 40.0 g/L with a hemicellulose sugars in a range of 5.5 - 6.6 g/L. These values are suitable for downstream bioconversion processes and represent a significant improvement over existing steam pretreatment methods.

Valorization of outer tunic of the marine filter feeder Ciona intestinalis towards the production of second-generation biofuel and prebiotic oligosaccharides.

BACKGROUND: One of the sustainable development goals focuses on the biomass-based production as a replacement for fossil-based commodities. A novel feedstock with vast potentials is tunicate biomass, which can be pretreated and fermented in a similar way to lignocellulose. Ciona intestinalis is a marine filter feeder that is cultivated to produce fish feed. While the inner tissue body is used for feed production, the surrounding tunic remains as a cellulose-rich by-product, which can be further separated into outer and inner tunic. Ethanol production from organosolv-pretreated whole-tunic biomass was recently validated. The aim of the present study was to evaluate the potential of organosolv pretreated outer-tunic biomass for the production of biofuels and cellobiose that is a disaccharide with prebiotic potential. RESULTS: As a result, 41.4 g/L of ethanol by Saccharomyces cerevisiae, corresponding to a 90.2% theoretical yield, was achieved under the optimal conditions when the tunicate biomass was pretreated at 195 °C for 60 min at a liquid-to-solid ratio of 50. In addition, cellobiose production by enzymatic hydrolysis of the pretreated tunicate biomass was demonstrated with a maximum conversion yield of 49.7 wt. %. CONCLUSIONS: The utilisation of tunicate biomass offers an eco-friendly and sustainable alternative for value-added biofuels and chemicals. The cultivation of tunicate biomass in shallow coastal sea improves the quality of the water and ensures sustainable production of fish feed. Moreover, there is no competition for arable land, which leaves the latter available for food and feed production.

Organosolv lignin hydrophobic micro- and nanoparticles as a low-carbon footprint biodegradable flotation collector in mineral flotation.

Flotation is a key step during mineral separation. Xanthates are the most commonly used collectors for recovering Cu, Ni, and Zn from sulphide ores. However, xanthates are fossil-based and toxic for the environment. The aim of this study was to evaluate the use of lignin nanoparticles and microparticles as sustainable and environmentally friendly collectors. Lignin particles demonstrated good selectivity toward Cu (chalcopyrite), with total recoveries exceeding 80% and grades of up to 8.6% w/w from a Cu-Ni ore in rougher flotation tests. When floating Zn-Pb-Cu ore, lignin nanoparticles could reduce the use of xanthates by 50%. Moreover, they outperformed xanthates alone, achieving total recoveries of up to 91%, 85%, and 98% for Cu, Pb, and Zn, respectively. These results prove the potential of lignin as a flotation collector.

A novel approach for the production of green biosurfactant from Pseudomonas aeruginosa using renewable forest biomass.

The rising demand for surfactants by the pharmaceuticals and cosmetic industries has generated vast amounts of petroleum-based synthetic surfactants, which are often toxic and non-degradable. Owing to their low toxicity, stability in extreme conditions, and biodegradability, biosurfactants could represent a sustainable alternative. The present study aimed to maximize the production of rhamnolipids (RL) from Pseudomonas aeruginosa by optimizing glucose concentration, temperature, and C/N and C/P ratios. After 96 h of cultivation at 37 °C, the final RL concentration was 4.18 ± 0.19 g/L with a final yield of 0.214 ± 0.010 g/gglucose when pure glucose was used as a carbon source. At present, the main obstacle towards commercialization of RL production is economic sustainability, due to the high cost of downstream processes and media components. For this reason, a renewable source such as wood hydrolysates (from birch and spruce woodchips) was examined here as a possible source of glucose for RL production. Both hydrolysates proved to be adequate, resulting in 2.34 ± 0.17 and 2.31 ± 0.10 g/L of RL, respectively, and corresponding yields of 0.081 ± 0.006 and 0.089 ± 0.004 g/gsugar after 96 h. These results demonstrate the potential of using renewable biomass for the production of biosurfactants and, to the best of our knowledge, they constitute the first report on the use of wood hydrolysates for RL production.

Sustainable biorefinery concept for biofuel production through holistic volarization of food waste.

The aim of this study was to utilize the whole food waste in two stages. In the first stage, the carbohydrate and protein fractions of food waste recovered after enzymatic hydrolysis was used to cultivate heterotrophic microalgae, resulting in biomass yield of 0.346 ±â€¯0.09 g/gsugars and lipid yield of 0.216 ±â€¯0.06 g/gsugars. In the second stage, oil (14.15% w/w) was extracted from food waste after hydrolysis and converted to biodiesel by a two-step transesterification reaction that generated 135.8 g/kgfood waste of fatty acid methyl esters and 13.8 g/kgfood waste of crude glycerol. Finally, crude glycerol obtained from both processes was used at 20 g/L to cultivate heterotrophic microalgae, resulting in a cell dry weight and total lipid concentration of 6.23 g/L and 2.91 g/L, respectively. A total 248.21 g of fatty acid methyl esters were obtained from the 1 kg of food waste through this integrated process.

Biosynthesis of Nutraceutical Fatty Acids by the Oleaginous Marine Microalgae Phaeodactylum tricornutum Utilizing Hydrolysates from Organosolv-Pretreated Birch and Spruce Biomass.

Polyunsaturated fatty acids (PUFAs) are essential for human function, however they have to be provided through the diet. As their production from fish oil is environmentally unsustainable, there is demand for new sources of PUFAs. The aim of the present work was to establish the microalgal platform to produce nutraceutical-value PUFAs from forest biomass. To this end, the growth of Phaeodactylum tricornutum on birch and spruce hydrolysates was compared to autotrophic cultivation and glucose synthetic media. Total lipid generated by P. tricornutum grown mixotrophically on glucose, birch, and spruce hydrolysates was 1.21, 1.26, and 1.29 g/L, respectively. The highest eicosapentaenoic acid (EPA) production (256 mg/L) and productivity (19.69 mg/L/d) were observed on spruce hydrolysates. These values were considerably higher than those obtained from the cultivation without glucose (79.80 mg/L and 6.14 mg/L/d, respectively) and also from the photoautotrophic cultivation (26.86 mg/L and 2.44 mg/L/d, respectively). To the best of our knowledge, this is the first report describing the use of forest biomass as raw material for EPA and docosapentaenoic acid (DHA) production.