Brandon A. Yoza

The analysis of macroalgae biomass found around Hawaii for bioethanol production.

Macroalgae commonly found in the ocean around Hawaii were collected from near shore locations and their potential as biomass feedstock for fermentative ethanol was investigated. A green alga, Ulva reticulata, was selected for further analysis. This species forms large complex structures that grow quickly and has high dry biomass percentage (20%), soluble carbohydrates (18%), and high total carbohydrates along with low quantities of lignin (13%). During acid saccharification, it was determined that 49% of the total mass was observed as sugars in the hydrolysate; however, fermentation was problematic. Enzymatic saccharification using cellulase from Trichoderma reesei was attempted which recovered a measured maximum of 20% glucose based on the initial dry mass. Fermentation successfully converted all the glucose to ethanol. The measured ethanol yield corresponded to approximately 90 L per tonne of dried macroalgae.

Increasing Thermal Stability of Gelatin by UV-Induced Cross-Linking with Glucose.

The effects of ultraviolet (254 nm) radiation on a hydrated gelatin-glucose matrix were investigated for the development of a physiologically thermostable substrate for potential use in cell scaffold production. Experiments conducted with a differential scanning calorimeter indicate that ultraviolet irradiation of gelatin-glucose hydrogels dramatically increases thermal stability such that no melting is observed at temperatures of at least 90°C. The addition of glucose significantly increases the yield of cross-linked product, suggesting that glucose has a role in cross-link formation. Comparisons of lyophilized samples using scanning electron microscopy show that irradiated materials have visibly different densities.

Evaluation of an up-flow anaerobic sludge bed (UASB) reactor containing diatomite and maifanite for the improved treatment of petroleum wastewater

Novel diatomite (R1) and maifanite (R2) were utilized as support materials in an up-flow anaerobic sludge bed (UASB) reactor for the treatment of recalcitrant petroleum wastewater. At high organic loadings (11kg-COD/m3·d), these materials were efficient at reducing COD (92.7% and 93.0%) in comparison with controls (R0) (88.4%). Higher percentages of large granular sludge (0.6mm or larger) were observed for R1 (30.3%) and R2 (24.6%) compared with controls (22.6%). The larger portion of granular sludge provided a favorable habitat that resulted in greater microorganism diversity. Increased filamentous bacterial communities are believed to have promoted granular sludge formation promoting a conductive environment for stimulation methanogenic Archaea. These communities had enhanced pH tolerance and produced more methane. This study illustrates a new potential use of diatomite and maifanite as support materials in UASB reactors for increased efficiency when treating refractory wastewaters.

Efficiencies and mechanisms of ZSM5 zeolites loaded with cerium, iron, or manganese oxides for catalytic ozonation of nitrobenzene in water

Discharge of industrial wastewater causes water pollution. It is therefore necessary to treat wastewater prior to discharge. Catalytic ozonation processes (COP) using ZSM5 zeolites loaded with metallic (Ce, Fe, or Mn) oxides to remove nitrobenzene from water were investigated. The total organic carbon (TOC) removal by the COP treatment with NaZSM5-38, HZSM5-38, and NaZSM5-100 were increased by 6.7%, 23.1%, and 19.8%, respectively, in comparison with single ozonation efficiency (39.2%). The loadings of Ce, Fe, or Mn oxides increased the catalytic activity relative to ZSM5 zeolites alone. The Ce loaded material (Ce/NaZSM5-38) had the highest TOC removal (86.3%). The different-metallic-oxides loaded zeolites exhibited different chemical processes during the removal of nitrobenzene from water. During COP treatment, NaZSM5-38 zeolites removed nitrobenzene mainly via OH mediated oxidation. HZSM5-38 and NaZSM5-100 zeolites showed powerful adsorption toward nitrobenzene. Both adsorption and direct ozonation contribute the TOC removal in their early uses. The OH mediated oxidation dominates the TOC removal process as the adsorption became saturated after multiple uses. Surface SiO bonds and/or SiO(H)Al structures are the active sites for ZSM5 zeolites. Efficient surface dispersion of the metallic oxides enhances the catalytic activity. This study shows the high potentials of ZSM5 zeolites as catalysts in COP to efficiently treat refractory wastewaters.

Internal Gas Exchange Photobioreactor

Two eight-tube internal gas exchange photobioreactors were deployed on an inclined platform at an ocean-front research facility in Honolulu, Hawaii. The photobioreactors consisted of 3.8-cm inside diameter, 20-m long tubes joined at the bottom to a manifold aerator and at the top to a degassing reservoir, with a total volume of 230 L and a nominal culture volume of 200 L. The eight-tube bioreactors were operated with the two outside tubes unaerated, thus establishing a recirculating flow through the bioreactors. Arthrospira (Spirulina) sp. was cultured using Zarrouk’s medium. Cultures were monitored daily by analyzing samples for dry weights and optical cell densities. An automated system recorded incident light, culture temperature, pH, and dissolved oxygen concentrations. Carbon dioxide was supplied once a day by bubbling pure CO2 through the culture. As needed, cultures were cooled by a sprinkler system. Cultures were inoculated from laboratory stocks into a single-tube outdoor bioreactor at a density of less than 0.2 g/L, and maintained under 80% shade cloth to prevent photooxidation. Initial instantaneous growth rates ranged from 0.3 to 0.5 per day with final densities up to 2.5 g/L. An initial trial with a dilution of 30% per day under a 50% shade cloth demonstrated a productivity of about 1 g/L/day over a six-day period and an average of 0.7 g/L/day for a 19-day period. The utility of tubular photobioreactors for the development of a biophotolysis process is being explored further.

Diversity of Archaea Communities within Contaminated Sand Samples from Johnston Atoll

ABSTRACT A molecular 16S rRNA gene (SSU rDNA) analysis was performed for the determination of Archaea communities in polycyclic aromatic hydrocarbon (PAH)- and polychlorinated biphenyl (PCB)-contaminated sand samples obtained from Johnston Atoll. The objective of this study was to investigate Archaea community structure and phylogenetic diversity in a PAH- and PCB-contaminated marine environment that may potentially be intrinsically bioremediating these compounds. The clones obtained from this analysis were equally represented between the Crenarchaeota and Euryarchaeota phyla. This isolated marine environment is predominantly reef habitat, suggesting that the xenobiotic compounds introduced over time influenced the community structure of autochthonous Archaea. Phylogenetic diversity within these samples suggests that the resident Archaea populations were only distantly related to cultivated taxa and cloned sequences found in the public domain from both marine and terrestrial origins.

Potential of wheat bran to promote indigenous microbial enhanced oil recovery

Microbial enhanced oil recovery (MEOR) is an emerging oil extraction technology that utilizes microorganisms to facilitate recovery of crude oil in depleted petroleum reservoirs. In the present study, effects of wheat bran utilization were investigated on stimulation of indigenous MEOR. Biostimulation conditions were optimized with the response surface methodology. The co-application of wheat bran with KNO3 and NH4H2PO4 significantly promoted indigenous MEOR (IMEOR) and exhibited sequential aerobic (O-), facultative (An-) and anaerobic (A0-) metabolic stages. The surface tension of fermented broth decreased by approximately 35%, and the crude oil was highly emulsified. Microbial community structure varied largely among and in different IMEOR metabolic stages. Pseudomonas sp., Citrobacter sp., and uncultured Burkholderia sp. dominated the O-, An- and early A0-stages. Bacillus sp., Achromobacter sp., Rhizobiales sp., Alcaligenes sp. and Clostridium sp. dominated the later A0-stage. This study illustrated occurrences of microbial community succession driven by wheat bran stimulation and its industrial potential.

Laboratory studies of rice bran as a carbon source to stimulate indigenous microorganisms in oil reservoirs

There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery (IMEOR) processes. In the present study, the potential of rice bran as a carbon source for promoting IMEOR was investigated on a laboratory scale. The co-applications of rice bran, K2HPO4 and urea under optimized bio-stimulation conditions significantly increased the production of gases, acids and emulsifiers. The structure and diversity of microbial community greatly changed during the IMEOR process, in which Clostridium sp., Acidobacteria sp., Bacillus sp., and Pseudomonas sp. were dominant. Pressurization, acidification and emulsification due to microbial activities and interactions markedly improved the IMEOR processes. This study indicated that rice bran is a potential carbon source for IMEOR.

Characterization of aerobic granular sludge used for the treatment of petroleum wastewater

The application of aerobic granular sludge (AGS) is a promising biological method for wastewater treatment. In the present study, the AGS method was used for the treatment of petroleum wastewater. The granulation process and organic/nitrogen compound removal efficiencies were determined and correlated with the microbiological communities. Granulation of the aerobic sludge occurred after 35 days of operation. The compacted granules had a diameter of 0.46-0.9 mm. Extracellular polymeric substances (EPS) contents increased as granulation progressed and reached 128 mg/g·VSS. The granulated sludge efficiently reduced COD by 95% and petroleum compound contents by 90%. NH4+-N and TN removal were inefficient due to the inhibition of nitrobacteria and denitrificans, but were significantly improved by the addition of glucose. The microorganisms in the granules capable of degrading petroleum chemicals consisted of the genera Propioniciclava, Micropruina, Alphaproteobacteria, Flavobacterium, and Sulfuritalea.

Turf soil enhances treatment efficiency and performance of phenolic wastewater in an up-flow anaerobic sludge blanket reactor

Phenols are industrially generated intermediate chemicals found in wastewaters that are considered a class of environmental priority pollutants. Up-flow anaerobic sludge blanket (UASB) reactors are used for phenolic wastewater treatment and exhibit high volume loading capability, favorable granule settling, and tolerance to impact loads. Use of support materials can promote biological productivity and accelerate start-up period of UASB. In the present study, turf soil was used as a support material in a mesophilic UASB reactor for the removal of phenols in wastewater. During sludge acclimatization (45-96 days), COD and phenols in the treatments were both reduced by 97%, whereas these contents in the controls were decreased by 81% and 75%, respectively. The phenol load threshold for the turf soil UASB reactor was greater (1200 mg/L, the equivalent of COD 3000 mg/L) in comparison with the control UASB reactor (900 mg/L, the equivalent of COD 2250 mg/L) and the turf soil UASB reactor was also more resistant to shock loading. Improved sludge settling, shear resistance, and higher biological activity occurred with the turf soil UASB reactor due to the formation of large granular sludge (0.6 mm or larger) in higher relative percentages. Granular sludge size was further enhanced by the colonization of filamentous bacteria on the irregular surface of the turf soil.