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Wastewater sludge is used as an alternative fuel due to its high organic content and calorific value. However, influent characteristics and operational practices of wastewater treatment plants (WWTPs) can increase the sulfur content of sludge, devaluing it as a fuel. Thus, we investigated the biochemical mechanisms that elevate the sulfur content of sludge in a full-scale industrial WWTP receiving wastewater of the textile dyeing industry and a domestic WWTP by monitoring the sulfate, sulfur, and iron contents and the biochemical transformation of sulfate to sulfur in the wastewater and sludge treatment streams. A batch sulfate reduction rate test and microbial 16S rRNA and dsrB gene sequencing analyses were applied to assess the potential and activity of sulfate-reducing bacteria and their effect on sulfur deposition. This study indicated that the primary clarifier and anaerobic digester prominently reduced sulfate concentration through biochemical sulfate reduction and iron–sulfur complexation under anaerobic conditions, from 1247 mg/L in the influent to 6.2~59.8 mg/L in the industrial WWTP and from 46.7 mg/L to 0~0.8 mg/L in the domestic WWTPs. The anaerobic sludge, adapted in the high sulfate concentration of the industrial WWTP, exhibited a two times higher specific sulfate reduction rate (0.13 mg SO42−/gVSS/h) and sulfur content (3.14% DS) than the domestic WWTP sludge. Gene sequencing analysis of the population structure of common microbes and sulfate-reducing bacteria indicated the diversity of microorganisms involved in biochemical sulfate reduction in the sulfur cycle, supporting the data revealed by chemical analysis and batch tests.

Aims Global warming and eutrophication contribute to the severity of cyanobacteria blooms. However, it is unclear how these factors influence the growth and toxin production of Anagnostidinema carotinosum. Methods and Results Based on morphological and molecular analysis, this is the first time A. carotinosum was identified in South Korea. The interactive effect of temperature (25, 30 or 34°C) and nitrogen (2.5, 3.5 or 4.5 mg NO3-N l−1) on A. carotinosum growth and toxin production was studied. Increasing nitrogen limitation reflects reduced growth and chlorophyll-a content at all temperatures. However, the growth was effective under nitrogen limitation when temperatures exceeded 25°C. The maximum growth was found at 30°C, followed by 34°C under higher nitrate levels (3.5 and 4.5 mg l−1). In addition, the cell microcystin and anatoxin-a quota increased significantly at 25°C with increasing nitrate limitation, decreasing considerably at 30°C in the same nitrate gradient. Conclusion These results suggested temperatures stimulate A. carotinosum growth at 30 and 34°C and cellular toxin quota at 25 and 34°C with increasing NO3-N levels. Significance and Impact of the Study These findings imply that limiting nitrogen input alone can effectively reduce biomass; however, controlling A. carotinosum and its toxins at higher temperatures under nitrate limitation is necessary for water quality.

Changes in physico-chemical factors due to natural climate variability and eutrophication could affect the cyanobacterial growth patterns in aquatic systems that may cause environmental health problems. Based on morphological and 16S rRNA gene analysis, three cyanobacterial species isolated for the first time from the Nakdong River water sample in South Korea were identified as Amazoninema brasiliense, Microcystis elabens, and Nododsilinea nodulosa. The variations in temperature, pH, nitrogen, or phosphorus levels significantly impacted the cyanobacterial growth patterns. The optimal temperature range for the growth of isolates was from 25-30°C. A neutral or weak alkaline environment favored growth; however, A. brasiliense resulted in 44.2-87.5% higher biomass (0.75 g · L-1 as dry solids, DS) and growth rate (0.24 · d-1 ) at pH 7 than the other isolates (0.4-0.52 g DS · L-1 , 0.16-0.19 · d-1 ). The increased nitrate-nitrogen (NO3 -N) concentrations significantly (P

A study was conducted to determine how melatonin (MLT), a growth regulator, affects Microcystis aeruginosa cell behaviour and how MLT exposed cells respond to hydrogen peroxide (H

This study examined the growth characteristics and competitive interaction of two cyanobacteria, Phormidium autumnale GJ_2B_I1 and Nostoc sp. DS_2B_I1, which were newly isolated from a southeast river (Nakdong) during the cyanobacterial harmful algal bloom (CyanoHAB) season in Korea. As major environmental parameters, the water temperature (25 and 30°C) and alkalinity (19 to 78 mg CaCO3 L-1 ), and nitrate concentration (1.5 to 3.5 mg NO3 -N L-1 ) were selected based on the water environmental monitoring data during the CyanoHAB season. Unlike P. autumnale, Nostoc sp. has a relatively high growth rate under both monoculture and co-culture and prefers the maximum environmental conditions (30°C and 78 mg CaCO3 L-1 /pH-9) during the CyanoHAB season. In addition, the growth of P. autumnale is relatively unaffected by alkalinity. Nitrogen stress also has a limiting effect in the interspecific interactions of both cyanobacterial strains. All other cases except for Nostoc sp. in a co-culture showed a considerable increase in growth rate with increasing nitrogen content (from 1.5 to 3.5 mg NO3 -N L-1 ), showing 20 - 64% under the minimum field conditions (25°C and 19 mg CaCO3 L-1 /pH-7) and 18 - 140% under the maximum field conditions. The results show that the growth of P. autumnale can be stimulated by enhanced nitrogen stress. On the other hand, Nostoc sp. is less affected by nitrogen stress compared to P. autumnale. Therefore, it has excellent potential to be a major group of CyanoHABs because of their relatively high growth rate, particularly in a range of nitrogen tested. This article is protected by copyright. All rights reserved.

Several organic compounds released into the aquatic environment have a detrimental impact on humans and other organisms. There is a lack of knowledge about natural hormones and herbicides on non-target organisms, including cyanobacteria. In this study, the response of Microcystis aeruginosa to four phytohormones, indole-3-acetic acid (IAA; 10−5), zeatin (ZT; 10−5), abscisic acid (ABA; 10−7), and brassinolide (BRL; 10−9 mol/L), exposed to terpinolene (TPN; (0.44, 0.88, 1.17, or 1.62 mmol/L) at the cellular and genetic levels were investigated. The results showed that TPN could inhibit the growth and photosynthetic activities and stimulate microcystins (MCs) of M. aeruginosa at various levels through the co-occurrence of oxidative stress, antioxidant defense activities, and an imbalance of the antioxidative system. Hormones played critical roles in the growth promotion and photosynthetic activity by enhancing the antioxidant defense mechanisms and MCs production of M. aeruginosa under TPN stress in both hormone and TPN dose-dependent manner. The growth performance and photosynthetic activities of M. aeruginosa were significant with IAA (p

Changes in physico-chemical factors due to natural climate variability and eutrophication could affect the cyanobacterial growth patterns in aquatic systems that may cause environmental health problems. Based on morphological and 16S rRNA gene analysis, three cyanobacterial species isolated for the first time from the Nakdong River water sample in South Korea were identified as Amazoninema brasiliense, Microcystis elabens, and Nododsilinea nodulosa. The variations in temperature, pH, nitrogen, or phosphorus levels significantly impacted the cyanobacterial growth patterns. The optimal temperature range for the growth of isolates was from 25-30°C. A neutral or weak alkaline environment favored growth; however, A. brasiliense resulted in 44.2-87.5% higher biomass (0.75 g · L

This study is aimed at investigating the performance of the continuous-flow, two-stage anaerobic column for the reductive dechlorination of perchloroethene (PCE) in a trichloroethene (TCE)-contaminated aquifer without bioaugmentation. Results indicated that complete dechlorination of PCE to cis-dichloroethene (DCE) was observed within the first 12 days after the addition of lactate and PCE (620:1 mg mg−1 mass ratio). The PCE conversion to ethene was initially observed in the 2nd column after 70 days (during phase II) upon the increase of lactate to PCE mass ratio to 5000:1 (mg mg−1). However, the degradation of PCE to ethene occurred in the 1st column after 30 days operation of phase IV (217–310 d) under the high PCE feed conditions (33.65 ± 2.86 μM). 16S rDNA clone library sequence analysis confirmed that Dehalobacter sp., Desulfuromonas sp., Desulfovibrio sp. Geobacter sp., Methanosaeta sp., Methanobacterium paludism, and M. spelaei were the dominant species in the original aquifer, and their relative abundance were further changed following lactate addition. Dehalococcoides mccartyi sequences were retrieved after lactate stimulation. Overall, the continuous-flow, two-stage anaerobic column process exhibited the maximum dechlorination (6.23 μmol L−1 hr−1) of PCE without bioaugmentation, indicating its potential up-scaling application in PCE dechlorination.

The development of cost-effective bioreactors and scalable methods for the high quantities of bacteriophage production meets the global demand for phage therapy. This study demonstrates the potential application of a novel PES-STiO2 nanocomposite membrane (NCM) to maintain the bacteriophages, increase the adsorption rate, and productivity in the phage enrichment reactor (PER). A constant volume of freshly grown Escherichia coli cells in tryptic soy broth (TSB) medium (first phase) was tainted with Escherichia phage in PER (second phase) in a cyclic process. Subsequently, the bacteria-phage filtrate and phage lysate samples were removed from the PER through the external cross-flow membrane reactor and the outlet of the PER at each cycle, respectively. The PER performed with the membrane had shown higher phage titers and productivity in the phage lysate at each cycle than those achieved from the PER w/o NCM (control). The phage productivity was increased (∼107 to 1013 PFU mL−1 cycle−1) with the increase in cycles and was higher than those from the control, and other reported reactors. As detected with the electron scanning microscope (SEM) and flux test, the NCM operated with bacteria-phage could able to prevent biofouling without their loss. Thus, the PES-STiO2 nanocomposite membrane integrated PER is simple and can be used at an industrial scale to maintain the volumetric phage production and higher phage productivity.