Tag Archives: residues

370-400 I. Berzina, S. Raita, M. Kalnins, K. Spalvins and I. Kuzmika
In search of the best technological solutions for creating edible protein-rich mutants: a multi-criteria analysis approach
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In search of the best technological solutions for creating edible protein-rich mutants: a multi-criteria analysis approach

I. Berzina*, S. Raita, M. Kalnins, K. Spalvins and I. Kuzmika

Riga Technical University, Institute of Energy Systems and Environment, Azenes street 12/1, LV 1048, Riga, Latvia
*Correspondence: Indra.Berzina@rtu.lv

Abstract:

Single-cell protein (SCP) is a promising alternative for replacing plant and animal-derived dietary proteins. SCP contains essential nutrients and high levels of essential amino acids (AA). Given the versatility of microbial strains and waste substrates that can be used as feedstocks, many variations of production processes can be explored. Improving these microorganism strains by enhancing their properties and productivity is vital to increasing SCP competitiveness. One of the options to enhance microorganism strains would be by creating mutants with better AA profiles. By using mutagenesis and AA inhibitors it should be possible the create novel strains with improved AA-producing properties. The use of AA inhibitors to promote selective pressure on SCP-producing strains is a novel concept and is not a widely explored approach, therefore, the further development of this method should be explored. This paper used a multi-criteria decision analysis method to evaluate different technological factors vital for creating protein-rich mutants. These factors are microorganism strains, agro-industrial waste substrates used as process feedstocks, AA inhibitors, and mutagenesis methods. Microorganisms Candida utilis and Bacillus subtilis showed the highest potential for being used. Molasses was the ‘closest to the ideal’ substrate to be used as feedstock for SCP production. As the most promising mutagenesis method ethyl methane sulphonate was selected. Glufosinate ammonium and methionine sulfoximine for both bacteria and fungi were identified as the best inhibitors for SCP-rich mutant selection. Identified combinations of optimal solutions for microorganisms, substrates, inhibitors, and mutagenesis techniques should be further investigated and evaluated in laboratory settings. This could help to increase SCP’s competitiveness as a sustainable protein source.

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149-155 A. Menind, L. Oper, M. Hovi, J. Kers, M. Tutt and T. Kikas
Pretreatment and usage of pulp and paper industry residues for fuels production and their energetic potential
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Pretreatment and usage of pulp and paper industry residues for fuels production and their energetic potential

A. Menind¹, L. Oper², M. Hovi¹, J. Kers³, M. Tutt¹ and T. Kikas¹

¹Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56,
EE51014 Tartu, Estonia; e-mail: andres.menind@emu.ee
²Institute of Economics and Social Sciences, Estonian University of Life Sciences,
Kreutzwaldi 1, EE51014 Tartu, Estonia; e-mail: liis.oper@emu.ee
³Department of Polymer Materials, Tallinn University of Technology;
e-mail: jaan.kers@ttu.ee

Abstract:

This paper gives an overview about Pulp and Paper Industry (PPI) residues, their properties and some solutions for converting those materials into fuels. The main leftovers are bark, sludge of aerobic digestion, primary floto sediment (PFS) and pulp rejects (PR). PFS and PR after applying dewatering (press fluids) have considerable biogas potential. Bark and press cake of PR are a good resource for briquetting. Ethanol potentials of bark and PR cake are presented.

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331-342 M. Luna-del Risco, A. Normak and K. Orupõld
Biochemical methane potential of different organic wastes and energy crops from Estonia
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Biochemical methane potential of different organic wastes and energy crops from Estonia

M. Luna-del Risco¹, A. Normak¹ and K. Orupõld¹²

¹Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences. Kreutzwaldi 5, 51014 Tartu, Estonia
²Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences
e-mail: 1 mario.luna@emu.ee, 1 argo.normak@emu.ee, 1,2 kaja.orupold@emu.ee

Abstract:

 The biochemical methane potential (BMP) of different Estonian substrates as alternative sources for biogas production was studied. For this purpose, the BMP test was carried out in batch mode at mesophilic temperature (36°C). Substrates were divided into 2 groups: agricultural substrates (silage, hay, cattle and pig slurry) and food industry residues (milk, brewery and cereal industry residues). Methane yields obtained were between 286–319 L kgVS-1 for silage and hay, 238–317 L kgVS-1 for animal slurry and 272–714 L kgVS-1 for agro-industrial wastes. The highest methane yield was obtained from sour cream (714    L kgVS-1), the lowest (238 L kgVS-1) from cattle slurry. In overall, our results suggest that all tested substrates can be treated anaerobically and are potential sources for the production of methane.

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