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This study investigated the effects of cyanobacteria from pulp-and-paper waste-treatment systems on biological toxicity removal and biodegradation of certain wastewater contaminants. In field and batch studies, using the Microtox®assay, cyanobacterial biomass and final wastewater toxicity were significantly correlated. In softwood-based wastewater, a decrease in toxicity was negatively correlated with cyanobacterial biomass, but the correlation was positive in hardwood-based wastewater. In the softwood-based wastewater, toxicity remained higher in the light than it was in the dark, whereas in hardwood-based wastewater, toxicity was lower in the light than it was in the dark. All of these results were light-dependent, suggesting that the photosynthetic growth of cyanobacteria is required to induce significant effects. When grown in mixed cultures with bacterial degraders, cyanobacteria from pulp-and-paper waste-treatment systems generally impeded the biodegradation of the wastewater contaminants phenol and dichloroacetate (DCA). However, there was one case where the cyanobacterium Phormidium insigne improved the bacterial degradation of DCA. Doubling inorganic nutrient concentrations did not improve phenol or DCA biodegradation in the majority of cases, indicating that nutrient competition is not a major factor. These data suggest that cyanobacteria play an important role during the biological treatment of contaminants, and, hence, toxicity removal in pulp-and-paper waste-treatment systems.Key words: cyanobacteria, heterotrophic bacteria, biodegradation, pulp and paper waste-treatment, wastewater toxicity.

The ability to differentiate functional and structural diversity of bacterial communities present in activated sludges adapted to elementally (ECF) and totally (TCF) chlorine-free bleaching effluents was evaluated. Community function was evaluated through substrate utilization patterns in BiologGN®microplates, and taxonomic structure was evaluated by fluorescent in situ hybridization using probes targeting the Eubacteria; the alpha, beta, and gamma subclasses of the Proteobacteria; and gram-positive bacteria with high GC content. Over 6-week sampling periods, ECF- and TCF-adapted sludge bacterial communities presented reproducible substrate utilization patterns that through principal components (PCs) analysis, separated the ECF samples from the TCF samples. Application of the fluorescent in situ hybridization technique was complicated by the intense autofluorescence of the bleaching effluent sludge samples that interfered with detection of specific hybridization signals. The most notable difference in community structure detected using the chosen set of probes was the relatively greater proportion of cells of the alpha subclass in TCF sludge (27%) than in ECF sludge (6%). Nonspecific hybridization with beta and gamma probes was relatively high, but both sludges appeared to have similar proportions of cells of the beta (20–22%) and gamma (11–12%) subclasses. The two sludges presented relatively few gram-positive cells with high GC content (

The relationship between the abundance of three functional genes and their corresponding biochemical reaction rates was investigated in several activated sludge and mill effluent microbial communities. Gene probes were prepared for two key denitrification genes (nirS and nirK) and for one nitrogen-fixation gene (nifH) and were validated using a variety of strains of known nir and nif genotype. ATP-based measures of viable cell numbers were used to provide total population sizes. In certain microbial communities (activated sludge enrichment cultures and multiple samples taken from the same mill primary clarifier), a strong correlation was observed between gene abundance and biochemical activity rates. However, when comparing several different nonenriched activated sludge bioreactors and separate primary clarifier microbial communities, the ratio of specific gene abundance to biochemical activity rates varied widely. These results suggest that in cases where a microbial community is not fully induced for a given biochemical activity or when very different communities are compared, quantitative gene probing can give a better measure of a community's potential to carry out the encoded function than can the relevant biochemical assay. However, the gene quantitation method employed here probably underestimated the true number of probed genes present in the microbial communities due to nirS and nifH genes in the communities having reduced DNA sequence similarity with the probes used.Key words: denitrification, nitrogen fixation, quantitative hybridization, activated sludge, primary clarifier.

A mixed culture in which cellulose is capable of being converted to methane and carbon dioxide was obtained from an inoculum procured from a sewage-treatment plant and maintained in a synthetic medium containing tissue paper and an inorganic salt and vitamin mixture. The culture was tested for its ability to degrade 12 different paper and cotton products under batch conditions in 3-ℓ anaerobic fermenters. This culture degraded 6–8 mmol/ℓ per week of cellulose, expressed as glucose equivalents, with total gas yields of 0.3 m3/kg of cellulose degraded. The gas produced contained between 56 and 59% of methane. Maximum cellulose degradation occurred at chemical oxygen demand: nitrogen: phosphorus level of 80:5:1 and was adversely affected by high stirring rate. Also the presence of higher proportions of lignin in cellulose products adversely affected the ability of this culture to degrade cellulose.

The coliform flora of a pulp and cardboard mill that uses birch as the raw material and ammonium sulphate as the process chemical was studied. Escherichia coli was observed to multiply in the mill. It persisted as the dominant thermotolerant coliform in the effluent. Klebsiellae were encountered among total coliforms only. The E. coli strains isolated had the biochemical characteristics and maximum growth temperatures typical to the species. However, serotyping and hemolysin test differentiated these strains from pathogenic and fecal E. coli.

Alternaria solani produced two homogeneous exocellular polysaccharide fractions when grown in shake culture with fructose as the carbon source and the NH4NO3 concentration of the medium 1.7 g/l. Chromatographic techniques indicated that fraction I contained glucose, galactose, and glucosamine in a 2.4:1:1 ratio whereas fraction II contained glucose, galactose, and mannose in a 6.4:1:1.2 ratio. Fraction I was found at levels seven times greater than II. Total polysaccharide produced was 1.8% of the dry weight of the mycelium and 1.2% of the available carbohydrate.Growth and polysaccharide production were greatest with fructose as the carbon source. Decreasing levels of growth occurred with mannitol, glucose, and sucrose, respectively. Exocellular polysaccharides were not detected with mannitol as carbon source. At 10 days, growth on fructose is maximum at NH4NO3 concentrations of 1.5 to 2.5 g/l, but exocellular polysaccharide production is maximum at 0.8 g/l. When produced on a medium of 2.0 g/l NH4NO3 the nitrogen content of I is double that when the medium is 0.8 g/l NH4NO3. In addition the ratio of I to II is about four times greater.

Multiple electrophoretic species of arylsulfatase were demonstrated in sonicates of Proteus rettgeri by paper electrophoresis. Subsequent treatment of the sonicates with streptomycin sulfate and DEAE-cellulose chromatography resolved enzyme activity into four fractions. Electrophoretic examination of each chromatographic fraction revealed sulfatase heterogeneity comparable to that of the initial extract. These electrophoretic components differed in their general response to a number of arylsulfatase inhibitors. The results are discussed in relation to the finding of multiple species of arylsulfatase in other biological systems.