Tajana Krička

Progress in ethanol production from corn kernel by applying cooking pre-treatment

In order to improve technological properties of corn kernel for ethanol production, samples were treated with a hydrothermal pre-treatment of cooking (steaming), prior to drying. Two types of cooking process parameters were applied; steam pressure of 0.5 bars during a 10 min period, and steam pressure of 1.5 bars during a 30 min period. Afterwards, samples were dried at four different temperatures, 70, 90, 110 and 130 degrees C. Control sample was also submitted to the aforementioned drying parameters. Since the results showed that starch utilization, due to the gelatinization process, was considerably higher in the samples pre-treated before the ethanol production process, it was found that the cooking treatment had a positive effect on ethanol yield from corn kernel. Therefore, the highest ethanol yield was found in the corn kernel samples cooked for 30 min at steam pressure 1.5 bars and dried at 130 degrees C. Due to the similarity of processes used for starch fermentation, introduction of cooking pre-treatment will not significantly increase the overall ethanol production costs, whereas it will result in significantly higher ethanol yield.

Bioethanol production from corn kernel grown with different cropping intensities.

The aim of this paper is to determine the level of influence of the applied cropping intensity on the water release speed from the kernel on the field and in the process of convection drying, on the content of starch and on the yield of ethanol in five different corn hybrids belonging to the same vegetation group.

Biomass valorisation of Arundo donax L., Miscanthus × giganteus and Sida hermaphrodita for biofuel production

Abstract In the context of the growing demand for biomass, which is being encouraged by the EU directives on the promotion of the use of renewable energy, recent investigations have been increasingly focused on fast-growing energy crops. The aim of this study was to investigate the energy properties of three types of agricultural energy crops: Arundo donax L., Miscanthus × giganteus and Sida hermaphrodita. This investigation looked into the content of non-combustible and combustible matter, higher and lower heating values, lignocellulose content, and biomass macro-elements. The results indicate that the energy values of these crops are comparable, while their lignocellulose content shows significant variations. Thus, Arundo donax L. can best be utilised as solid biofuel due to its highest lignin content, while Miscanthus × giganteus and Sida hermaphrodita L. can be used for both liquid and solid biofuels production. As far as Arundo donax L. is concerned, a higher ash level should be taken into consideration.

High-risk biodegradable waste processing by alkaline hydrolysis.

High-Risk Biodegradable Waste Processing By Alkaline Hydrolysis Biodegradable waste is by definition degraded by other living organisms. Every day, meat industry produces large amounts of a specific type of biodegradable waste called slaughterhouse waste. Traditionally in Europe, this waste is recycled in rendering plants which produce meat and bone meal and fat. However, feeding animals with meat and bone meal has been banned since the outbreaks of bovine spongiform encephalopathy (BSE). In consequence, new slaughterhouse waste processing technologies have been developed, and animal wastes have now been used for energy production. Certain parts of this waste, such as brains and spinal cord, are deemed high-risk substances, because they may be infected with prions. Their treatment is therefore possible only in strictly controlled conditions. One of the methods which seems to bear acceptable health risk is alkaline hydrolysis. This paper presents the results of an alkaline hydrolysis efficiency study. It also proposes reuse of the obtained material as organic fertiliser, as is suggested by the analytical comparison between meat and bone meal and hydrolysate. Oporaba visokorizičnog biorazgradivog otpada metodom alkalne hidrolize Biorazgradivi otpad definira se kao otpad koji razgrađuju živi organizmi. Klaonice i mesna industrija proizvode na dnevnoj bazi velike količine specifičnoga biorazgradivog otpada poznatog kao otpad životinjskog podrijetla. Tradicionalno se u Europi taj otpad reciklira u kafilerijama, pri čemu se proizvode mesno-koštano brašno i mast. No nakon pojave goveđe spongiformne encefalopatije (GSE) zabranjena je prehrana životinja mesno-koštanim brašnom. U potrazi za novim mogućnostima zbrinjavanja otpada životinjskog podrijetla razvijene su nove tehnologije oporabe i omogućena upotreba takvog otpada u energetske svrhe. Određeni dijelovi otpada životinjskog podrijetla, mozak i leđna moždina, pripadaju kategoriji visokorizičnog otpada zbog velike mogućnosti postojanja priona u njima. Njihova oporaba stoga je moguća samo u strogo kontroliranim uvjetima. Jedna od metoda koja se smatra prikladnom za oporabu visokorizičnih otpada jest metoda alkalne hidrolize. U radu su prikazani rezultati analiza mesno-koštanog brašna i hidroliziranog otpada te njegova uporaba kao organskoga gnojiva.

Anaerobic digestion of specific biodegradable waste and final disposal

The present paper investigates the effectiveness of different levels of applied digested residue obtained after anaerobic digestion (AD) of meat-bone meal (MBM) on the morphologic and mineral characteristics of corn. The experiment was conducted in duration of two years and consisted of eight treatments: control (without any fertilizer) ; mineral fertilization only ; treatments with minimum, medium and maximum dosage of digested MBM ; combined fertilization of minimum, medium and maximum dosages of AD residue combined with mineral fertilizer. Combination of treatments with mineral fertilizer and different rate s of AD residue, plants had increased mass yield, they were larger and had more leaves. Contents of mineral substances were within average values, both in plant material and in kernel, and variations in values were conditioned by total mass and ion interactions. MBM after AD treatment is possible to apply as organic fertilizer. It has higher nutritive value and, as such, is suitable for treatment of agricultural plants, especially in crop production.

High-risk bio-waste processing by alkaline hydrolysis and isolation of amino acids

Slaughterhouse waste can be very dangerous and potential risk for animal and human health. Brains and spinal cords are deemed high-risk substances and can be infected with prions ; their treatment is therefore only possible in strictly controlled conditions. One of the methods which can achieve the necessary reduction in health risk is alkaline hydrolysis. Standard alkaline hydrolysis is at 150°C, 3-6 hours, and 4 bars. In this investigations focus was on different alkaline conditions: temperature (135oC, 150oC, 153oC), time (2, 3, 6 hours), and base (NaOH and KOH) due to fact that amino acids are sensitive to variations on temperature, pressure and base media. Analyzed amino acid composition of hydrolyzed material at different testing conditions show successful hydrolysis. Highest value of protein, which is generally relatively low, was achieved with NaOH at a temperature of 135oC and time of 2 hours, whereas in the reaction with KOH the highest obtained value was achieved at 150oC and 3 hours. A dry substance increasing with time, and the highest value was achieved at the temperature of 150oC and time 6 hours for both bases (NaOH, and KOH). Most of the amino acids went full racemization during the process ; especially in D-amino acids like aspartic acid, glutamic acid, tryptophan and isoleucine. Lysine shows higher resistance to alkaline medium than other amino acids. Isolation of certain amino acids, like: asparagine, glutamic acid, glycine, alanine, and leucine, is possible because they show higher concentrations in hydrolysates.

Energy valorization of Miscanthus x giganteus biomass: A case study in Croatia

The aim of this study is to determine the calorific values, chemical composition (proximate and ultimate analysis, micro and macro elements) and cell structure (composition of lignocellulose) of Miscanthus x giganteus biomass cultivated in Croatian. Research results represents the average values of biomass (n = 108) cultivated at two locations in Croatia (Bistra, Medvednica), during the three-year research period, three harvest periods (autumn, winter, spring) per year and two fertilizer treatments (N0 i N50). Determined average values of some important parameters are: low calorific value - 17.25 MJ/kg, ash content - 1.49 %, carbon content - 48.75 %, nitrogen content - 0.47 %, sulfur content - 0.07 %, cellulose content - 49.22 % and lignin content - 29.25 %. The obtained results have shown that Miscanthus x giganteus has potential to be a significant source of good quality raw material in the production of solids biofuels.

Effects of different air drying temperature on sunflower seeds oil and ash content

The aim of this paper was to determine the impact of different air temperature (60 °C, 80 °C and 100 °C) at air drying velocity of 1.0 ms-1 during convection drying thermal process on the sunflower seeds oil and ash content. The research was conducted at 4 different sunflower seeds hybrid Apollo, NK Brio, PR 63 and PR 90 A 63 D 82, which by their characteristics are early and medium early hybrids.. Based on the results, the curve of water speed release from the sunflower seeds, the activation energy, as well as changes in oil content and ash content before and after the convective drying was obtained. It was established that the NK Brio hybrid fastest release water compared to other hybrids during drying which is confirmed by minimum value of activation energy and that the increasing of air drying temperature increases oil content, while reduces ash content.

MINERAL COMPOSITION OF CORN PLANT MATERIAL AFTER FERTILIZATION WITH FERMENTED MEAT-BONE MEAL

Based on the conducted investigations, after a two-year research of meat-bone meal as a biofertilizer (in 8 combinations and 3 repetitions) on corn hybrids, it can be determined that the lowest plant mass was recorded in the control combination, where no fertilizer was applied, and somewhat higher plant mass was recorded in those combinations where organic fertilizers in different dosages were applied. A significant increase in plant mass was found in combinations with only mineral fertilizer applied and in combinations with half dosage of mineral fertilizer and different shares of organic fertilizer. Further, plants were larger and had larger number of leaves when treated with half-dosage mineral fertilizer in combination with different dosages of organic fertilizer, and when treated with mineral fertilizer only. The fertilizer tests with fermented MBM enable to conclude that the mineral substances content (N, P2O5, K2O, Ca and Mg) ranged in mean values both in plant material and in kernel, and different values are conditioned by total mass and ion interactions.