Browsing by Subject "mikrolevä"

Microalgae are promising raw materials for food- and biotechnology because they contain a lot of proteins, unsaturated fatty acids, pigments, vitamins and minerals. There are few studies on vitamin B in microalgae and some of them are based on partly inaccurate methods. Microalgae in general, analytical methods regarding their analysis and how they use vitamins were discussed in the literature part of this thesis. The structures, chemical properties and occurrence in foods as well as commonly used analytical methods of the vitamins in question were presented. The aim of the experimental part of this thesis was to analyse commercially marketed microalgae supplements (Chlorella sp. and Arthrospira sp. (spirulina)) and laboratory-grown microalga (Euglena gracilis) as potential sources of folate, niacin, vitamin B2 and B12. Contents of vitamin B12, B2 and niacin were analysed using UHPLC method separately validated for each vitamin. The total folate content was analysed microbiologically and folate vitamers by using UHPLC. The vitamin B12 was analysed microbiologically and the active forms of vitamin B12 were confirmed using LC-MS. Acid hydrolysis was used in analysing niacin content. The total folate content in chlorella supplements was of the same order when analysed microbiologically or with UHPLC. Instead, in spirulina supplements the microbiologically analysed total folate content was higher than the total folate content based on the sum of folate vitamers analysed with UHPLC. At most, the total folate content of E. gracilis -sample was 3-fold higher than in commercial microalgae supplements. Especially in spirulina supplements, the vitamin B12 contents were clearly higher when analysed microbiologically than they were when analysed with UHPLC. The difference was most likely due to pseudocobalamin that resembled vitamin B12. On average E. gracilis -samples had higher vitamin B2 content than the commercial supplements. E. gracilis -samples and chlorella supplements contained more niacin than spirulina supplements. According to this thesis, commercially marketed microalgae supplements contained different amounts of vitamin B. Chlorella sp. was proved to be a great source of folate, vitamin B12 and niacin and moderate source of B2. The majority of vitamin B12 in Arthrospira sp. (spirulina) was pseudocobalamin. Despite that, spirulina supplements proved to be a moderate source of vitamin B12. On average, E. gracilis had the highest vitamin B content and it would potentially be an excellent source of vitamin B – if it was accepted for food use.

Microalgae are unicellular organisms with excellent nutritional composition, ability to efficiently produce biomass and low environmental demands. The use of microalgae in animal feeds is common in aquaculture and newly introduced to animal husbandry. There is a growing need for alternative protein feeds to diminish the environmental cost of feed production and competition with food production. This research examined if soy protein can be replaced with microalgal protein in concentrate feeding of dairy cows. The effect of protein source on feed intake, milk production, milk composition, amino acid intake and use in mammary gland as well as plasma metabolites were evaluated. The feeding experiment was conducted in the research farm of the University of Helsinki in the summer of 2014. The study design was a 4x4 Latin square with four multiparous ayrshire dairy cows and four different experimental diets (isonitrogenously soybean meal (Glycine max), Spirulina platensis, Chlorella vulgaris or 1:1 mixture of Chlorella and Nannochloropsis gaditana as protein feed). The experimental concentrates (12.5 kg/d) were based on cereals and molassed sugarbeet pulp. The cows were given grass silage ad libitum. The physiological feeding experiment lasted for 12 weeks, with four experimental periods of three weeks. Feed intake was recorded and samples of feed, milk, feces and blood were taken to determine the effect of the experimental feeds on the cows. Inclusion of microalgae lowered the intake of concentrate feeds, but overall dry matter intake remained unchanged as the intake of grass silage was increased. The only effect on milk production and milk composition was the slightly higher fat concentration of milk when microalgal feeds were fed. In plasma, acetic acid and free fatty acid concentrations were higher and insulin concentrations lower when feed included microalgae, and also the mammary metabolism of these metabolites was affected by the experimental diets. The results refer to slight changes in rumen fermentation and mammary gland metabolism when microalgae replaced soy in the feeds. The effects of different feeds on amino acid metabolism were minor. Based on mammary uptake-output ratio, the most limiting amino acid in all diets seemed to be methionine. Based on the results of this experiment, microalgal feeds are equal or even slightly superior to soy as a protein feed of dairy cows when it comes to nutritional composition and productive responses. Inferior palatability of microalgae compared to soy, high production costs of microalgal feeds and lack of systematic scientific research are nevertheless hindering the large-scale commercial use of microalgae in domestic animal feeds.

PURPOSE AND GOALS Microalgae are unicellular eukaryotic organisms capable of photosynthesis. They harvest sunlight and efficiently take up carbon dioxide and nutrients such as nitrogen and phosphorus from their environment and use them for their growth. Due to these properties, their rapid growth and ability to survive in a variety of environments, microalgae have potential in biotechnological applications that promote nutrient recovery and recycling, water purification and the carbon neutral production of biochemicals and possibly biofuels. The purpose of this study was to investigate the suitability of a side stream water originating from the production of baker’s yeast (yeastwater) for the cultivation of a species of microalga called Euglena gracilis. The study aimed to determine the capacity of this water to support growth and protein production of E. gracilis as well as the capacity of E. gracilis to remove nutrients from the water. The effect of filtration of the water on these parameters was also studied. Yeastwater contains an organic molecule called betaine in relatively high concentrations. Betaine has previously been shown to boost the production of the important vitamin cobalamin in bacteria. The study aimed to determine the effect of betaine on the growth of E. gracilis and on the production of cobalamin in the algal-bacterial symbiosis. METHODS E. gracilis was cultured in laboratory scale photobioreactors. Its growth, protein production and nutrient uptake capacity was determined. Baker’s yeast production side stream water diluted with MQ-water was used as the growth medium either in filtered or unfiltered form. A control treatment was prepared where no microalgal inoculate was added to the photobioreactor. The same microalga was also grown in a synthetic nutrient medium with and without betaine. The uptake of betaine and biomass concentrations of cobalamin were determined. For the determination of microalgal growth, dry weight determination and flow cytometry analysis were used. Protein production was determined on the basis of total nitrogen concentration in the biomass. Spectrophotometric measuring kits were used for the determination of nutrient concentrations. Liquid chromatography techniques were used for the determination of betaine and cobalamin concentrations. RESULTS Significant microalgal growth was observed in filtered yeastwater, while growth in unfiltered yeastwater was very low. Nitrogen removal was higher in presence of E. gracilis compared to the control treatment. Protein production in yeastwater was comparable to that of microalgae grown in synthetic medium. E. gracilis grew much better in the synthetic media supplemented with betaine than without the addition. Betaine enrichment had no effect on cobalamin production. Cobalamin was produced in unfiltered yeastwater both with and without the presence of E. gracilis. CONCLUSIONS Unfiltered yeastwater does not support growth of E. gracilis possibly due to its high turbidity. Filtered yeastwater, on the other hand can support the production of E. gracilis biomass. E. gracilis can be used to reduce nitrogen concentrations in yeastwater. Yeastwater can support cobalamin production by bacteria, but this phenomenon did not benefit from the presence of the microalga. The effect of betaine on microalgal growth warrants further study to determine whether it is related to the accumulation of intracellular nutrients, storage compounds or to some other phenomenon. Yeastwater is a promising nutrient feedstock for microalgal biomass production. However, the role of filtration and possibility of using other methods for turbidity reduction needs to be further studied.

In order to increase protein self-sufficiency and food production, it is necessary to study new protein feeds. Faba bean (Vicia faba) is a nitrogen-fixing plant, and thereby a good choice for versatile rotation of crops. Faba beans contain less crude protein and considerably more starch than rapeseed meal. Most of the faba bean protein degrades in rumen and it contains less methionine than rapeseed meal protein. Microalgae contain plenty of crude protein and their production requires less surface area than cultivation of field crops. Microalgae can also be grown in harsh climate conditions. However, microalgae have, in some of the earlier studies, reduced palatability of the diet. Aim of this Master’s Thesis was to compare rapeseed meal, faba bean seeds and Spirulina microalgae effects on feed intake and milk production of dairy cows. Hypothesis were decreased feed intake when Spirulina was added to the diet; lower milk production with faba bean diet than with rapeseed diet; and increased milk production when a part of faba bean protein was replaced with Spirulina protein. The study was conducted at Viikki research farm at Helsinki during the spring of 2015. Eight multiparous ayrshire dairy cows were used. At the beginning of the study, on average 113 days were passed since calving of the cows. The study design was a replicated 4 x 4 Latin square. Cows of the other square were rumen fistulated. Treatments (rapeseed, rapeseed + Spirulina, faba bean, faba bean + Spirulina) were isonitrogenous. In microalgae treatments protein from Spirulina was used to substitute half of the protein from rapeseed or faba bean. Total mixed ration (TMR) included in addition to protein feeds grass silage, barley, molassed sugar beet pulp and vitamins and minerals. Cows received TMR ad libitum. There were no differences in dry matter intake (DMI) between rapeseed and faba bean treatments. According to the hypothesis, DMI was decreased with Spirulina diets. Hypothesis regarding milk production were also realised. Milk, energy-corrected milk, fat, protein and lactose yields were lower with faba bean than with rapeseed treatments. Adding Spirulina to diet increased milk yield in faba bean treatment, but decreased it in rapeseed treatment. Adding Spirulina to diet did not affect energy-corrected milk yield significantly. Spirulina did not affect fat yields, and it lowered the protein and lactose yields in rapeseed treatment, and increased them in faba bean treatment. Based on the findings of the study, faba bean and Spirulina are inferior protein feeds compared to rapeseed meal in grass silage and grain based diets. Faba bean protein’s high rumen degradability and low methionine concentration probably limit milk production. Spirulina and faba bean combined meet dairy cow’s amino acid needs better than faba bean alone. However, Spirulina’s negative impact on DMI may restrict its usage as a protein feed for dairy cows.

Lots of protein feeds are imported to Europe. In Finland at most 25 % of all protein feeds used are home-grown. Legumes and single-cell protein are of interest to replace imported protein feeds. The aim of this study was to explore faba bean (Vicia faba) and Spirulina-algae (Spirulina platensis) as protein source for dairy cows. The study design was replicated 4 x 4 Latin square with four diets and four periods of three weeks. The experiment was 2 x 2 factorial. Rapeseed meal and rolled faba bean were compared as protein sources. The partial replacement (half) of rapeseed meal and faba bean protein with Spirulina-algae was also investigated. All the protein supplements were isonitrogenous. In this study, effects of protein supplements on dry matter intake, milk yield and milk composition, production of microbial protein in the rumen, plasma amino acids and mammary uptake of amino acids and nitrogen partitioning were examined. This study was made at the research farm of the University of Helsinki in 21.2.–15.5.2015. There were eight multiparous Finnish ayrshire dairy cows at mid-lactation. The cows were divided in two blocks the other block having rumen fistulated animals. All the total mixed ratios contained grass silage of good quality, barley, sugar pulp and minerals supplemented with different protein sources. Cows were offered total mixed ratios ad libitum. Replacing rapeseed meal and faba bean with Spirulina-algae reduced dry matter intake. The milk yield was 1,4 kg/d greater on rapeseed meal diets compared with faba bean diets. Mixing Spirulina-algae with faba bean increased milk, protein and lactose yields, but when mixed with rapeseed meal decreased them. Both milk urea and rumen ammonia concentrations were higher in faba bean diets than in rapeseed meal diets. The concentration of several essential amino acids in plasma and mammary uptake of histidine and methionine were lower in faba bean diets than in rapeseed meal diets. Replacing faba bean partially with Spirulina increased AV-difference of essential amino acids. Nitrogen balances were positive in all experimental diets. There were no differences in nitrogen intake. Feeding faba beans reduced nitrogen secretion in milk and faeces compared to rapeseed meal diets. Replacing rapeseed meal and faba bean partially with Spirulina increased the proportion of nitrogen secreted in urine and lowered nitrogen balance. According to this study replacing rapeseed meal completely with faba bean seeds reduce milk and protein yields on diets based on grass silage and cereals. Mixing Spirulina with faba bean increased milk, protein and lactose yields, but decreased them when mixed with rapeseed meal. Protein of faba bean and Spirulina probably completed each others. More research is needed with high levels of micro algae on dry matter intake, animal performance and degradability of microalgal protein in rumen.