Zygomycetes and cellulose residuals : hydrolysis, cultivation and applications

Zygomycetes is a class of fungi living worldwide as saprobes, as part of mycorrhizae, and as parasites. Humans have used some zygomycetes for centuries in the production of traditional foods, e.g. Indonesian tempe. In the present thesis, the experimental focus was on two zygomycetes strains, Mucor indicus CCUG 22424 and Rhizopus sp. IT. One of the distinguishing features of M. indicus is its dimorphism. The different cell forms were influenced by the culturing conditions. After inoculation, when the initial spore concentration was high (6-8×106 spores/ml), yeast-like growth dominated under anaerobic conditions. With a smaller inoculum, yielding 1-2×105 spores/ml, and access to oxygen, filamentous forms dominated. Only negligible differences in ethanol yield (390-420 mg/g hexoses), productivity (3-5 g/l/h), and inhibitor tolerance were observed. Differential expressions of probably four genes were observed between the yeast-like and filamentous growth forms. Lignocelluloses are a suitable substrate for cultivating zygomycetes, as they occur in abundance, particularly since zygomycetes, unlike Saccharomyces cerevisiae, can utilise pentoses. Lignocelluloses require pretreatment to achieve efficient hydrolysis of the cellulose. N-methylmorpholine-N-oxide (NMMO) was tested for pretreatment of spruce and birch. Reducing wood chip size and/or prolonged pretreatment, promoted hydrolysis yield. Best yields were achieved from &lt;2 mm chips and 5 h pretreatment. The hydrolysate was used for fermentation with M. indicus, resulting in 195 and 175 mg ethanol/g wood, and 103 and 86 mg fungal biomass/g wood, from spruce and birch respectively. Orange peel is another potential substrate. However, the hydrolysate contained 0.6 % (v/v) D-limonene, ten times higher than the concentration inhibiting S. cerevisiae. M. indicus was more resistant and successfully fermented the hydrolysate, producing 400 mg ethanol/g hexoses and 75 mg fungal biomass/g sugars. Both M. indicus and Rhizopus sp. grew in 1.0 % and 2.0 % D-limonene, although the latter was unable to grow in the hydrolysate. A third substrate was also used, spent sulphite liquor (SSL), which is a by-product from sulphite paper pulp mills. The SSL was diluted to 50 % and used for airlift cultivations of Rhizopus sp. In 1.0 vvm aeration, up to 340 mg biomass/g sugars was produced. Prolonged cultivations generally decreased the protein (from 500 to 300 mg/g) and lipid (from 70 to 20 mg/g) contents. In contrast, the cell wall fraction, measured as alkali-insoluble material (AIM), increased (160-280 mg/g), as did the glucosamine (GlcN) content (220-320 mg GlcN/g AIM). The produced fungal biomass could serve as animal feed, e.g. for fish.Akademisk avhandling som för avläggande av teknologie doktorsexamen vid Chalmers tekniska högskola försvaras vid offentlig disputation den 9 februari 2012, klockan 10.00 i KS101, Kemigården 4, Göteborg.</p

Antimicrobial effect of zygomycetes cell wall on nonwoven textiles

The goal of this thesis work was to investigate the antimicrobial effect of chitosan from zygomyzetes cell wall material in nonwoven textiles and compare it to commercially available chitosan. This was done using two methods, a somewhat modified version of AATCC Test Method 100-2004 (a standard method for quantitative testing of antimicrobial effect in textiles developed by the AATCC Committee) focusing on CFU, and TTC, a tetrazolium salt that changes from colourless to red in the presence of living microorganisms under the right conditions. The CFU method was also used to detect if it is possible to add chitosan earlier in the production stages, by scanning for any antimicrobial effect in test samples produced that way. Commercial chitosan added to the test samples in 2 % citric acid showed the strongest antimicrobial effect, even reaching the detection limit of approximately 99.5 % inhibition for both E. coli and K. pneumoniae without any incubation. Medium molecular weight commercial chitosan added in 2 % citric acid solution was also the only tested compound that could eliminate C. ablicans after 24 h incubation. Both commercial chitosan added as a powder and cell wall extract showed a mediocre inhibition without incubation, but were able to reach &gt;99 % inhibition after 24 h incubation. Generally speaking, the chitosan investigated is comparable to the chitosan available commercially today, even if it required somewhat longer to reach the same levels of inhibition. The other method for addition of chitosan, however, did not work properly.Uppsatsnivå:

Destruktivt entreprenörskap : Fusket/missbruket med assistansersättningen

Purpose: The aim is to investigate the mechanisms behind the destructive entrepreneurship in the assistance industry. Method: To investigate the destructive entrepreneurship in the assistance industry, we conducted a qualitative study in the form of semi-structured questions. In total, we interviewed four authorities and an employer organization. Theory: Theoretical framework: The study is based on Baumol's (1990) theory of productive, unproductive and destructive entrepreneurship and rent-seeking by Murphy et al (1991), but the study's principal theory that we have chosen to apply is the routine activity theory of Cohen &amp; Felson (1979) that describes three elements that must come together in order for a crime to be committed. Conclusions and discussion: Our study shows that it is clear that there is both fraud and abuse within the assistance allowance, which can be done in different ways. Some users simulate their illness that they exaggerate their need for assistance. Some assistance providers have abused the compensation by paying lower wages and empty false wages etc. The study showed that there also exists a type of human trafficking. The fraud/abuse includes millions of kroner and it requires several people to accomplish the embezzlement. The most common form in which cheating occurs is limited but it is suspected that the abuse occurs in all forms of assistance other than the cooperative assistance form. The assistance industry is not in a position of being undermined; however, compensation levels may be slightly compressed.Syfte: Syftet är att utreda mekanismerna bakom det destruktiva entreprenörskapet i assistansbranschen. Metod: För att undersöka det destruktiva entreprenörskapet i assistansbranschen har vi genomfört en kvalitativ undersökning i form av semistrukturerade intervjuer. Totalt intervjuade vi fyra myndigheter och en arbetsgivareorganisation. Teoretisk referensram: Studien utgår ifrån Baumols (1990) teori om produktivt, improduktivt samt destruktivt entreprenörskap och privilegiejaktsteorin av Murphy med flera (1991), men studiens huvudteori som vi har valt att tillämpa är rutinaktivitetsteorin av Cohen &amp; Felson (1979) som beskriver tre förutsättningar som måste sammanstråla för att ett brott ska kunna begås. Slutsats och Diskussion: Vår studie visar att det står klart att det förekommer både fusk och missbruk inom assistansersättningen vilket kan utföras på olika sätt. Från att vissa brukare simulerar sin sjukdom till att de överdriver sina assistansbehov. Vissa assistansanordnare har missbrukat ersättningen genom att betala lägre löner och t.o.m. falska löner mm. Studien visade att det också förekommer en typ av människohandel. Fusket/missbruket handlar om miljonbelopp och det krävs ett nätverk av personer för att åstadkomma förskingringen. Den vanligaste formen där fusket förekommer är aktiebolag men det misstänks att missbruket förekommer i alla assistansformerna utom den kooperativa assistansformen. Assistansbranschen riskerar dock inte att undermineras däremot kan ersättningsnivåerna komma att pressas något

Destruktivt entreprenörskap : Fusket/missbruket med assistansersättningen

Purpose: The aim is to investigate the mechanisms behind the destructive entrepreneurship in the assistance industry. Method: To investigate the destructive entrepreneurship in the assistance industry, we conducted a qualitative study in the form of semi-structured questions. In total, we interviewed four authorities and an employer organization. Theory: Theoretical framework: The study is based on Baumol's (1990) theory of productive, unproductive and destructive entrepreneurship and rent-seeking by Murphy et al (1991), but the study's principal theory that we have chosen to apply is the routine activity theory of Cohen &amp; Felson (1979) that describes three elements that must come together in order for a crime to be committed. Conclusions and discussion: Our study shows that it is clear that there is both fraud and abuse within the assistance allowance, which can be done in different ways. Some users simulate their illness that they exaggerate their need for assistance. Some assistance providers have abused the compensation by paying lower wages and empty false wages etc. The study showed that there also exists a type of human trafficking. The fraud/abuse includes millions of kroner and it requires several people to accomplish the embezzlement. The most common form in which cheating occurs is limited but it is suspected that the abuse occurs in all forms of assistance other than the cooperative assistance form. The assistance industry is not in a position of being undermined; however, compensation levels may be slightly compressed.Syfte: Syftet är att utreda mekanismerna bakom det destruktiva entreprenörskapet i assistansbranschen. Metod: För att undersöka det destruktiva entreprenörskapet i assistansbranschen har vi genomfört en kvalitativ undersökning i form av semistrukturerade intervjuer. Totalt intervjuade vi fyra myndigheter och en arbetsgivareorganisation. Teoretisk referensram: Studien utgår ifrån Baumols (1990) teori om produktivt, improduktivt samt destruktivt entreprenörskap och privilegiejaktsteorin av Murphy med flera (1991), men studiens huvudteori som vi har valt att tillämpa är rutinaktivitetsteorin av Cohen &amp; Felson (1979) som beskriver tre förutsättningar som måste sammanstråla för att ett brott ska kunna begås. Slutsats och Diskussion: Vår studie visar att det står klart att det förekommer både fusk och missbruk inom assistansersättningen vilket kan utföras på olika sätt. Från att vissa brukare simulerar sin sjukdom till att de överdriver sina assistansbehov. Vissa assistansanordnare har missbrukat ersättningen genom att betala lägre löner och t.o.m. falska löner mm. Studien visade att det också förekommer en typ av människohandel. Fusket/missbruket handlar om miljonbelopp och det krävs ett nätverk av personer för att åstadkomma förskingringen. Den vanligaste formen där fusket förekommer är aktiebolag men det misstänks att missbruket förekommer i alla assistansformerna utom den kooperativa assistansformen. Assistansbranschen riskerar dock inte att undermineras däremot kan ersättningsnivåerna komma att pressas något

Miljö eller avkastning? : en investeringsjämförelse mellan gammal och ny energi

The purpose with this study is to investigate funds that are environmentally friendly. Environment issues has become a large subject that affects all aspects in today’s society.  It is a global issue which has affected the awareness of environmentally friendly products and its benefits for the environment. How has this awareness affected the financial market?  In this study the authors have looked at six environmentally sound funds and six energy funds to answer the question if it´s better to have your money in traditional energy or in renewable energy. This study is made in an quantitative way, the data has been gathered from the internet database Morningstar.  The energy funds have had its biggest assets in companies dealing with oil, and the environmentally sound funds have had its biggest assets in renewable energy. Bye looking at the different funds rate of return and relating that to risk managing theories of Sharpe and Treynor, the authors compared the two types of funds. During the period that was looked at during this study ( third quarter of 2007 until third quarter 2010) the energy funds outperformed the environmentally sound funds in every aspect.

Introducing Computer Science in an Undergraduate Program Based on Problem-Based Learning by Means of Declarative System Modelling and Simulation

Abstract This paper presents the objective for and experience from using Dymola as “the first programming language” in an engineering curriculum in information technology. This curriculum is based entirely on the Problem Based Learning model, PBL, and on integration of the contents from different disciplines and different department. The curriculum started in the fall 1995, so there is still less than one year of experience. 1. The general objective for the curriculum The Information Technology Program at Linköping University is a new 4.5 year engineering program with three specific objectives: 1. To investigate and demonstrate the potential of Problem Based Learning as a general strategy for engineering education and training 2. To recruit 40 % or more female students (around 5 % is a common fraction in other engineerin

Mycelial pellet formation by edible ascomycete filamentous fungi, Neurospora intermedia

Pellet formation of filamentous fungi in submerged culture is an imperative topic of fermentation research. In this study, we report for the first time the growth of filamentous ascomycete fungus,Neurospora intermedia in its mycelial pellet form. In submerged culture, the growth morphology of the fungus was successfully manipulated into growing as pellets by modifying various cultivation conditions. Factors such as pH (2.0–10.0), agitation rate (100–150 rpm), carbon source (glucose, arabinose, sucrose, and galactose), the presence of additive agents (glycerol and calcium chloride) and trace metals were investigated for their effect on the pellet formation. Of the various factors screened, uniform pellets were formed only at pH range 3.0–4.0, signifying it as the most influential factor for N. intermedia pellet formation. The average pellet size ranged from 2.38 ± 0.12 to 2.86 ± 0.38 mm. The pellet formation remained unaffected by the inoculum type used and its size showed an inverse correlation with the agitation rate of the culture. Efficient glucose utilization was observed with fungal pellets, as opposed to the freely suspended mycelium, proving its viability for fast- fermentation processes. Scale up of the pelletization process was also carried out in bench-scale airlift and bubble column reactors (4.5 L)