Thesis (M. Sc.)--Carleton University, 2002. / Includes bibliographical references (p. 140-154). Also available in electronic format on the Internet.

Thesis (M.Sc.). / Written for the Dept. of Bioresource Engineering. Title from title page of PDF (viewed 2008/07/30). Includes bibliographical references.

The effect of simple and complex on the composition and diversity of microbial communities and on end-product (biogas and VFAs) synthesis was investigated using an anaerobic batch respirometer at 37 °C and pH 7.2. These experiments, simple substrates were chemically pure and contain a single carbon source (glucose or α-cellulose), while complex substrates were chemically “impure” substrates containing a mixture of two or three carbon sources (biodiesel-derived glycerol or wheat straw) with a substrate/inoculum ratio 6g chemical oxygen demand (COD)/ g volatile solids (VS) seed and 100g of pre-treated dairy manure digestate (DMD), respectively. Concentrations of hydrogen, carbon dioxide, acetate, butyrate, propionate, and ethanol synthesized by different communities selected by growth on the different substrates were measured and confirmed the growth of the microbial communities. 16S rDNA illumina sequencing revealed that DMD without substrates was more diverse than the microbiota cultured by fermentation reactions containing D-glucose, glycerol α-cellulose or wheat straw. The data confirmed that substrates play a crucial role in determining the diversity of species in microbial communities. Dominant operational taxonomic units (OTUs) belonging to families Clostridiaceae, Ruminococcaceae, and Enterobacteriaceae, and the genera Clostridium, Ruminococcus, Sporolactobacillus, and Syntrophomonas were potentially responsible for changes in end-product synthesis patterns in communities cultured with simple and complex substrates. / October 2015

Thesis (Master)--İzmir Institute of Technology, İzmir, 2004 / Includes bibliographical references (leaves. 59).

Thesis (Ph. D.)--Kansas State University, 2004. / Includes bibliographical references.

Manure from animal farms and sewage sludge contain pathogens and opportunistic organisms in various concentrations depending on the health of the herds and human sources. Other than for the presence of pathogens, these waste substances are excellent nutrient sources and constitute a preferred organic fertilizer. However, because of the pathogens, the risks of infection of animals or humans increase with the indiscriminate use of manure, especially liquid manure or sludge, for agriculture. This potential problem can increase with the global connectedness of animal herds fed imported feed grown on fields fertilized with local manures. This paper describes a simple, easy-to-use, low-tech hygienization method which conserves nutrients and does not require large investments in infrastructure. The proposed method uses the microbiotic shift during mesophilic fermentation of cow manure or sewage sludge during which gram-negative bacteria, enterococci and yeasts were inactivated below the detection limit of 3 log10 cfu/g while lactobacilli increased up to a thousand fold. Pathogens like Salmonella, Listeria monocytogenes, Staphylococcus aureus, E. coli EHEC O:157 and vegetative Clostridium perfringens were inactivated within 3 days of fermentation. In addition, ECBO-viruses and eggs of Ascaris suum were inactivated within 7 and 56 days, respectively. Compared to the mass lost through composting (15–57%), the loss of mass during fermentation (< 2.45%) is very low and provides strong economic and ecological benefits for this process. This method might be an acceptable hygienization method for developed as well as undeveloped countries, and could play a key role in public and animal health while safely closing the nutrient cycle by reducing the necessity of using energy-inefficient inorganic fertilizer for crop production.

Shellfish waste obtained from seafood processing plants contains chitin, protein and calcium carbonate. Chitin is a versatile biopolymer with many applications. Conventionally, chitin is separated from calcium carbonate and protein by acid and alkali respectively. In this project, a biotechnological approach was applied to recover chitin from scampi (Nephrops norvegicus) waste using lactic acid bacteria (LAB) to produce lactic acid from glucose which lowers the pH of the mixture, thus preserving the waste from spoilage. The acid also dissolves the calcium carbonate and under these conditions native enzymes breakdown the protein (autolysis), thus affording a substantial amount of purification of chitin. LAB were isolated and identified from various shellfish waste fermentations. Studies on their acid-producing ability revealed a few potentially good strains, identified as Lactobacillus paracasei, Lactobacillus plantarum and Pediococcus sp. The strain of Lactobacillus paracasei was used as a starter culture in the fermentation of shellfish waste in a horizontal rotating bioreactor in order to evaluate the feasibility of the process. The design of the bioreactor was such that it enabled separation of solid and liquid end products during fermentation. Several important fermentation parameters were studied including mode of rotation, concentration of glucose, temperature, rotation rates, loading capacity, type and particle size of waste. Partial purification of the scampi waste was achieved using both batch and fed batch operation, but in the latter, improved purification was achieved at the cost of increased glucose consumption and extended fermentation times. Whilst higher temperatures increased the rates of fermentation, higher rotation rates seemed to have the reverse effect. Mincing the waste helped to increase breakdown of protein whilst larger particles tended to undergo rapid spoilage. Analysis of the chitin product enabled this method to be compared with the conventional method. The results obtained showed that this method is capable of saving large volumes of chemicals and besides producing chitin, the protein liquor by-product could also be used as an ingredient in an animal feed which is not possible by the conventional method.

Via mixed-culture fermentation, the MixAlcoTM produces carboxylic acids, which are chemically converted into industrial chemicals and hydrocarbon fuels. Using pilot fermentation data, The Continuum Particle Distribution Model (CPDM) overestimated acid concentration (30–90% error) but more closely estimated conversion (<15% error). Incorporating the effect of air into the model reduced the absolute error of all predictions by >50%. To analyze fermentation data with semi-continuous streams, the Slope method calculates the average flowrate of material from the slope of the moving cumulative sum with respect to time. Although the Slope method does not significantly improve accuracy, it dramatically reduces error compared to traditional techniques (>40% vs. <2%). Nutrients are essential for microbial growth and metabolism. For a four-bottle fermentation train, five nutrient contacting patterns (single-point nutrient addition to Fermentors F1, F2, F3, F4, and multi-point parallel addition) were investigated. Compared to the traditional nutrient contacting method (all nutrients fed to F1), the near-optimal feeding strategies improved exit yield, culture yield, process yield, exit acetate-equivalent yield, conversion, and total acid productivity by approximately 31%, 39%, 46%, 31%, 100%, and 19%, respectively. To estimate nitrogen concentration profiles, a segregated-nitrogen model uses separate mass balances for solid- and liquid-phase nitrogen; the nitrogen reaction flux between phases is assumed to be zero. Using five fermentation trains, each with a different nutrient contacting pattern, the model predictions capture basic behavior; therefore, it is a reasonable tool for estimating and controlling nitrogen profiles. To determine the optimal scenario for mixed-acid fermentations, an array of batch fermentations was performed that independently varied the C/N ratio and the blend of carbohydrate (office paper) and nutrient (wet chicken manure (CM)). Reactant was defined as non-acid volatile solids (NAVS). C/N ratios were based on non-acid carbon (CNA). A blend of 93% paper and 7% wet CM (dry basis) with a C/N ratio of 37 g CNA/g N had the highest culture yield (0.21 g acidproduced/g NAVSinitial), total acid productivity (0.84 g acidproduced/(Lliq·d)), and conversion (0.43 g NAVSconsumed/g NAVSinitial).

Three New Zealand marine species, hoki (Macruronus novaezealandiae), kahawai (Arripis trutta) and trevally (Pseudocaranx dentex) were used to develop model fermented fish sausage. The formulation comprised fish mince, carbohydrate, minced garlic and salt in a mass ratio of 1 (fish): 0.15: 0.05: 0.03, respectively. The carbohydrate source was cooked rice or glucose. (Endogenous lactic acid bacteria (LAB) failed to ferment rice). Folate was also added to the mixture as a factor. The mixtures were extruded into 50 mL plastic syringes, where the needle end of the barrel had been excised by lathe. The lubricated barrel was overfilled to 60 mL, capped with a layer of ParafilmTM and aluminium foil, sealed tightly by rubber band and incubated at 30°C. Over time the piston was progressively advanced to yield samples for microbiological, physical, and chemical analysis. Over 96 hours an increase in the LAB count was observed with a concomitant decrease in pH. After fermentation was complete, the samples contained around 8.77 log cfu LAB g-1 with the pH range from 4.38 to 5.08. The microbiological and pH behaviour of each species varied between preparations. Hardness, adhesiveness, springiness and cohesiveness of the treatments increased with fermentation, except for hoki. The treatments showed different colour characteristics with fermentation. The light reflectance (L* values) of the trevally and kahawai treatments increased, while the a* (redness) and b* (yellowness) values decreased. Hoki exhibited smaller colour changes except for yellowness, which increased markedly. Proteolysis, measured colorimetrically by soluble peptide bonds, was greatest for trevally. Lipid oxidation, measured by the thiobarbituric acid method, was least for hoki, notably the species with the lowest fat content. Biogenic amines, which are a general quality indicator of fermented products, increased during fermentation. The trevally treatment generated the highest concentration of amines, but these values were lower than those reported for fermented fish sausage in Southeast Asia. Notably there were no important difference between folate treatments and those without folate. The results point to commercial opportunities and further research with New Zealand marine species, especially trevally. To improve the product quality and to show geographical exclusivity, further research could be done by using starter culture, and a New Zealand staple carbohydrate source such as kumara and potato, and spices and herbs which are commonly used in New Zealand, such as rosemary, thyme and sage or specific to New Zealand, such as horopito. In addition, sensory studies should also be performed before the products could be tested in the market.

Three New Zealand marine species, hoki (Macruronus novaezealandiae), kahawai (Arripis trutta) and trevally (Pseudocaranx dentex) were used to develop model fermented fish sausage. The formulation comprised fish mince, carbohydrate, minced garlic and salt in a mass ratio of 1 (fish): 0.15: 0.05: 0.03, respectively. The carbohydrate source was cooked rice or glucose. (Endogenous lactic acid bacteria (LAB) failed to ferment rice). Folate was also added to the mixture as a factor. The mixtures were extruded into 50 mL plastic syringes, where the needle end of the barrel had been excised by lathe. The lubricated barrel was overfilled to 60 mL, capped with a layer of ParafilmTM and aluminium foil, sealed tightly by rubber band and incubated at 30°C. Over time the piston was progressively advanced to yield samples for microbiological, physical, and chemical analysis. Over 96 hours an increase in the LAB count was observed with a concomitant decrease in pH. After fermentation was complete, the samples contained around 8.77 log cfu LAB g-1 with the pH range from 4.38 to 5.08. The microbiological and pH behaviour of each species varied between preparations. Hardness, adhesiveness, springiness and cohesiveness of the treatments increased with fermentation, except for hoki. The treatments showed different colour characteristics with fermentation. The light reflectance (L* values) of the trevally and kahawai treatments increased, while the a* (redness) and b* (yellowness) values decreased. Hoki exhibited smaller colour changes except for yellowness, which increased markedly. Proteolysis, measured colorimetrically by soluble peptide bonds, was greatest for trevally. Lipid oxidation, measured by the thiobarbituric acid method, was least for hoki, notably the species with the lowest fat content. Biogenic amines, which are a general quality indicator of fermented products, increased during fermentation. The trevally treatment generated the highest concentration of amines, but these values were lower than those reported for fermented fish sausage in Southeast Asia. Notably there were no important difference between folate treatments and those without folate. The results point to commercial opportunities and further research with New Zealand marine species, especially trevally. To improve the product quality and to show geographical exclusivity, further research could be done by using starter culture, and a New Zealand staple carbohydrate source such as kumara and potato, and spices and herbs which are commonly used in New Zealand, such as rosemary, thyme and sage or specific to New Zealand, such as horopito. In addition, sensory studies should also be performed before the products could be tested in the market.