Publications by authors named "Atte Mikkelson"

A combined pretreatment based on alkaline deep eutectic solvent (DES) of KCO and glycerol and sequential acid fractionation was developed to extract reactive lignin from wheat straw biomass. This process exhibited excellent purification performance in lignin isolation, and the lignin fractionated at low pH displayed high reactivity, having hydroxyl and carboxyl groups up to 9.60 and 2.

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Fast pyrolysis bio-oil (FPBO), a second-generation liquid bioenergy carrier, is currently entering the market. FPBO is produced from biomass through the fast pyrolysis process and contains a large number of constituents, of which a significant part is still unknown. Various analytical methods have been systematically developed and validated for FPBO in the past; however, reliable methods for characterization of acetaldehyde, formaldehyde, and furfural are still lacking.

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This study aims to examine the characteristics of two solid lignin fractions isolated from wheat straw using alkaline and acidic deep eutectic solvents (DESs). The chemical properties and morphological characteristics of the two lignin fractions were evaluated by measuring their purity, elemental composition, molecular weight and particle size distributions, and microstructure. Their chemical structure was evaluated using DRIFT (diffuse reflectance infrared Fourier transform) spectroscopy, GPC (gel permeation chromatography), TGA (thermogravimetric analysis), C NMR (nuclear magnetic resonance), P NMR, and HSQC NMR.

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Article Synopsis
  • * Ten different ascomycete yeast species were isolated from various sourdough types, and seven were tested for traits important for brewing, showing low alcohol production (<1%) during initial fermentation trials.
  • * Two yeast species, Kazachstania servazzii and Pichia fermentans, were chosen for larger fermentation tests; Pichia fermentans showed promise for low-alcohol wheat beers due to its spice aroma, while Kazachstania servazzii was suited for lager-style beers due to its clean flavor profile
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Article Synopsis
  • The study analyzed cell cultures from cloudberry, lingonberry, and stoneberry for their nutritional content, focusing on carbohydrates, lipids, proteins, and digestibility.* -
  • Results showed high protein levels (13.7-18.9%), significant dietary fiber (21.2-36.7%), and a rich profile of essential fatty acids, with glucose and fructose being the most common sugars.* -
  • Sensory evaluation revealed that fresh cultures had a pleasing aroma and a coarse texture, while the freeze-dried versions melted quickly in the mouth, confirming their potential as a food source.*
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The suitability of several abundant but underutilized agro and forest based biomass residues for hydrothermal treatment followed by enzymatic hydrolysis as well as for hydrothermal carbonization was studied. The selected approaches represent simple biotechnical and thermochemical treatment routes suitable for wet biomass. Based on the results, the hydrothermal pre-treatment followed by enzymatic hydrolysis seemed to be most suitable for processing of carbohydrate rich corn leaves, corn stover, wheat straw and willow.

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Even though size exclusion chromatography (SEC) with post column addition of calcofluor (SEC-calcofluor) has been used for the determination of cereal β-glucan molar mass in foods for many years, there is a lack of systematic evaluation of the method. To address this issue a set of suitable β-glucan standards were generated by preparative SEC and their molar mass characteristics were determined by analytical multi-detection SEC (refractive index (RI), light scattering). Each standard was then analysed by SEC-calcofluor at three different labs.

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Two bottles of beer from an about 170-year-old shipwreck (M1 Fö 403.3) near the Åland Islands in the Baltic Sea were analyzed. Hop components and their degradation compounds showed that the bottles contained two different beers, one more strongly hopped than the other.

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Microcrystalline cellulose was treated in supercritical water at 380 °C and at a pressure of 250 bar for 0.2, 0.4, and 0.

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In this paper we describe the enzymatic hydrolysis of konjac glucomannan for the production of glucomannooligosaccharides using purified Trichoderma reesei mannanase, endoglucanases EGI (Tr Cel7b) and EGII (Tr Cel5a). Hydrolysis with each of the three enzymes produced a different pattern of oligosaccharides. Mannanase was the most selective of the three enzymes in the hydrolysis of konjac mannan and over 99% of the formed oligosaccharides had mannose as their reducing end pyranosyl unit.

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