The use of selected purple nonsulfur bacteria to remove heavy metals and salts from sediment and water collected from contaminated areas to decrease their phytotoxicity

The potential of the purple nonsulfur bacteria (PNSB), NW16 and KMS24, to remove heavy metals (HMs) and salts was investigated in a synthetic solution (62.63 Pb2+, 34.60 Cu2+, 58.5 Zn2+ and 0.75 Cd2 mg/L) containing 3% NaCl, sediment, and water collected from contaminated post cultured shrimp ponds and seed germination of 2 plants were used to assay their plant toxicities after bioremediation. Both light metal ions (85 mg/L Ca2+ and 160 mg/L Mg2+ to the synthetic HMs solution) significantly decreased the HMs removal efficiency and the mixed culture gave the highest efficiency to remove HMs (removal percentages; 85 Pb2+, 74 Cu2+, 47 Zn2+ and 28 Cd2+). The best set for the treatment of contaminated water from shrimp ponds (Cu2+, Zn2+; 0.043, 0.057 mg/L and salinity, 10.23%0) under the conditions of aerobicdark and microaerobic-light was a set of native with added mixed culture with a decrease of roughly 75, 31 and 77% for Cu2+, Zn2+ and salinity, respectively. For the sediment samples, a set of native with added mixed culture also produced the highest efficiency to remove HMs (initial concentrations in mg/kg dry weight; 23.15 Pb2+, 15.05 Cu2+, 22.16 Zn2+ and 0.29 Cd2+) and salinity (0.84%0) under aerobicdark conditions with the removal percentages of HMs; 84.29, 62.52, 43.33 and 40.95, and 100% salinity. Consequently, this set produced the most effective treatment as the germination index was 34.50 and 35.29% for rice seed (Oryza sativa) and water spinach (Ipomoea aquatic) respectively in the treated water and 115.70 and 139.33% for rice and water spinach respectively in the treated sediment.Keywords: Bioremediation, contaminated shrimp ponds, heavy metals, photosynthetic bacteria, salinity, seed germination indexAfrican Journal of Biotechnology Vol. 11(29), pp. 7434-7444, 10 April, 201

Bioaugmentation of latex rubber sheet wastewater treatment with stimulated indigenous purple nonsulfur bacteria by fermented pineapple extract

AbstractBackgroundTreating latex rubber sheet wastewater often leads to the generation of a rotten-egg odor from toxic H2S. To increase the treatment efficiency and eliminate H2S, purple nonsulfur bacteria (PNSB), prepared by supplementing non-sterile rubber sheet wastewater (RAW) with fermented pineapple extract (FPE), were used to treat this wastewater under microaerobic light conditions. The following 3 independent variables: chemical oxygen demand (COD), initial pH and FPE dose were investigated using the Box–Behnken design to find optimal conditions for stimulating the growth of indigenous PNSB (PNSBsi).ResultsThe addition of 2.0% FPE into RAW, which had a COD of 2000mgL-1 and an initial pH of 7.0, significantly decreased oxidation reduction potential (ORP) value and stimulated PNSBsi to reach a maximum of 7.8logcfumL-1 within 2d. Consequently, these PNSBsi, used as inoculants, were investigated for their ability to treat the wastewater under microaerobic light conditions. A central composite design was used to determine the optimal conditions for the wastewater treatment. These proved to be 7% PNSBsi, 0.8% FPE and 4d retention time and this combination resulted in a reduction of 91% for COD, 75% for suspended solids, 61% for total sulfide while H2S was not detected. Results of abiotic control and treatment sets indicated that H2S was produced by heterotrophic bacteria and it was then effectively deactivated by PNSBsi.ConclusionsThe stimulation of PNSB growth by FPE under light condition was to lower ORP, and PNSBsi proved to be effective for treating the wastewater

The potential use of anoxygenic phototrophic bacteria for treating latex rubber sheet wastewater

A total of 92 isolates of the purple non sulphur photosynthetic bacteria (PNSB) were isolated from 23 samples of wastewater obtained from rubber sheet manufacturing processes from various places of southern, Thailand. The isolate DK6 had the best potential for use in wastewater treatment as it can out-compete indigenous strains of PNSB when grown with them under conditions of microaerobic-light conditions. The isolate DK6 was identified as being most closely allied to Rhodopseudomonas blastica . The optimal pH and temperature for cell growth were between 6.5-7.5 and 30\ub0C, respectively. Optimum growth of DK6 was obtained after supplementing the wastewater from a latex rubber sheet processing plant with 0.50% (NH4)2SO4 and 1 mg/L nicotinic acid under conditions of microaerobic-light (3000 lux). Using these optimum conditions for growth, indigenous microorganisms reduced the initial chemical oxygen demand (COD) of the wastewater from 7,328 to 3371 mg/L a reduction of 54% and the biochemical oxygen demand (BOD) (initial BOD 4967 mg/L) by 70%. Using the same conditions and either a pure culture of DK6 or a mixed culture (DK6 plus indigenous microorganisms) a reduction of 90% of both COD and BOD was achieved. Chemical analysis of the cultures after treatment of the enriched wastewater shows that the protein content of the pure DK6 was 65.2% of the dry weight, and in mixed culture the protein content was 66.7%. Hence, single cell protein (SCP) may be a possible bi- product of the treatment process

The use of rice straw broth as an appropriate medium to isolate purple nonsulfur bacteria from paddy fields

Abstract The aims were to explore an appropriate isolating medium for obtaining purple nonsulfur bacteria (PNSB) for use as biofertilizers in saline paddy fields and to obtain pure cultures. We therefore chose a defined isolating medium containing 0.25% NaCl, (Glutamate-Acetate broth, GA) and a rice straw broth to compare them for numbers of PNSB obtained, time to obtain pure cultures, diversity and costs. A total of 30 water and 30 sediment samples were collected from saline paddy fields in southern Thailand and used to isolate PNSB in both the isolating media. Based on 60 samples and a period of 13 days incubation under anaerobic light conditions, a greater number of samples produced PNSB growth in GA broth after only day 3; however, after that the rice straw broth provided about a 2 fold increase in the number of samples that produced PNSB growth. Colonies isolated from GA broth required a significantly higher number of repeated streaking to obtain a pure culture (average 3.5) than those from rice straw broth (average 2.7) and the latter medium also produced significantly (P < 0.05) more isolates per sample. Sixty samples of water and sediment, from rice paddies with salinity (average, 3.43 \ub1 0.67 mS/cm) and slight acidity (average, pH 5.84 \ub1 0.42) provided 62 PNSB isolates by GA broth and 210 isolates by rice straw broth, and rice straw broth also produced a greater prevalence of PNSB. Estimates of the costs based on current prices of media, Gas Pak and electricity to obtain PNSB with the use of GA broth was roughly 6 times higher than for the rice straw broth

Use of wood vinegar to enhance 5-aminolevulinic acid production by selected Rhodopseudomonas palustris in rubber sheet wastewater for agricultural use

AbstractThis study aimed to produce inexpensive 5-aminolevulinic acid (ALA) in a non-sterile latex rubber sheet wastewater (RSW) by Rhodopseudomonas palustris TN114 and PP803 for the possibility to use in agricultural purposes by investigating the optimum conditions, and applying of wood vinegar (WV) as an economical source of levulinic acid to enhance ALA content. The Box–Behnken Design experiment was conducted under microaerobic-light conditions for 96h with TN114, PP803 and their mixed culture (1:1) by varying initial pH, inoculum size (% v/v) and initial chemical oxygen demand (COD, mg/L). Results showed that the optimal condition (pH, % inoculum size, COD) of each set to produce extracellular ALA was found at 7.50, 6.00, 2000 for TN114; 7.50, 7.00, 3000 for PP803; and 7.50, 6.00, 4000 for a mixed culture; and each set achieved COD reduction as high as 63%, 71% and 75%, respectively. Addition of the optimal concentration of WV at mid log phase at 0.63% for TN114, and 1.25% for PP803 and the mixed culture significantly increased the ALA content by 3.7–4.2times (128, 90 and 131μM, respectively) compared to their controls. ALA production cost could be reduced approximately 31times with WV on the basis of the amount of levulinic acid used. Effluent containing ALA for using in agriculture could be achieved by treating the RSW with the selected ALA producer R. palustris strains under the optimized condition with a little WV additive

Isolation of purple nonsulfur bacteria for the removal of heavy metals and sodium from contaminated shrimp ponds

In order to determine whether waters used for the shrimp cultivation contained toxic levels of heavy metals (HMs) and sodium (Na), analysis was carried out on 31 shrimp ponds in areas of southern Thailand. Purple nonsulfur bacteria (PNB) were also isolated from the same ponds to investigate if they could be used for bioremediation of the above contaminants. The highest HMs concentrations of the sediment samples in mg/kg dry weight were found as follows: 0.75 cadmium (Cd), 62.63 lead (Pb), 34.60 copper (Cu) and 58.50 zinc (Zn). However, all sediment samples met Hong Kong standards for dredged sediment. In contrast, contamination of Cu (9-30 µg/L) and Zn (140-530 µg/L) exceeding the standard guidelines for marine aquatic animal set by the Pollution Control Department, Thailand, were found in 32 and 61% of water samples, respectively. Two metal resistant PNB isolates, NW16 and KMS24, were selected from the 120 PNB isolates obtained. Both isolates reduced the levels of HMs by up to 39% for Pb, 20% for Cu, 7% for Cd, 5% for Zn and 31% for Na from water that contained the highest levels of HMs found and 3% NaCl when cultured with either microaerobic-light or aerobic-dark conditions. The isolate NW16 removed a greater percentage of the HMs than the isolate KMS24, but the isolate KMS24 was able to survive better under a greater variety of environmental conditions. Both strains were therefore suitable to use for further investigating their abilities to remediate water contaminated with HMs and Na

Microbial succession in a fermenting of wild forest noni (Morinda coreia Ham) fruit plus molasses and its role in producing a liquid fertilizer

The numbers of lactic acid bacteria (LAB) and yeasts that were present during a wild forest noni (Morinda coreia Ham) fermentation, the changes in its physico-chemical properties and levels of plant nutrients were investigated. LAB increased rapidly during the first 7 days and were the dominant population until after day 21 when the LAB were declining and the yeasts began to dominate. Identification of the LAB and yeasts to species level showed that the dominant LAB throughout was Lactobacillus plantarum while Lactobacillus pentosus was found but only at day 21. Saccharomyces cerevisiae was the most dominant species of yeast throughout but was slowly replaced by Pichia membranifaciens and then Pichia anomala. Rhodotolura mucilaginosa, an aerobic yeast, was only detected at the beginning of the fermentation process. It is suggested that the Pichia spp. were responsible for consuming lactic acid. After 56 days, the values of pH, acetic acid, ethanol and electrical conductivity in the fermented product were 3.66, 3.34 g L-1, 16.98 g L-1 and 14.47 mS cm-1, respectively. Increased amounts of plant nutrients were present at day 56 mostly derived from the degradation of plant material. At day 56 the amounts were as follows (in mg L-1): N 633, P 1210, K 4356, Ca 693, Mg 536, Mn 7, B 51, Zn 169, and total carbon/total nitrogen ratio (C/N ratio) 18. Based on the seed germination index (GI) of cherry tomato (Lycopersicon esculentum Mill), the extract diluted 256-fold gave the best GI of 157%

Isolation of purple nonsulfur bacteria for the removal of heavy metals and sodium from contaminated shrimp ponds

In order to determine whether waters used for the shrimp cultivation contained toxic levels of heavy metals (HMs) and sodium (Na), analysis was carried out on 31 shrimp ponds in areas of southern Thailand. Purple nonsulfur bacteria (PNB) were also isolated from the same ponds to investigate if they could be used for bioremediation of the above contaminants. The highest HMs concentrations of the sediment samples in mg/kg dry weight were found as follows: 0.75 cadmium (Cd), 62.63 lead (Pb), 34.60 copper (Cu) and 58.50 zinc (Zn). However, all sediment samples met Hong Kong standards for dredged sediment. In contrast, contamination of Cu (9-30 \u3bcg/L) and Zn (140-530 \u3bcg/L) exceeding the standard guidelines for marine aquatic animal set by the Pollution Control Department, Thailand, were found in 32 and 61% of water samples, respectively. Two metal resistant PNB isolates, NW16 and KMS24, were selected from the 120 PNB isolates obtained. Both isolates reduced the levels of HMs by up to 39% for Pb, 20% for Cu, 7% for Cd, 5% for Zn and 31% for Na from water that contained the highest levels of HMs found and 3% NaCl when cultured with either microaerobic-light or aerobic-dark conditions. The isolate NW16 removed a greater percentage of the HMs than the isolate KMS24, but the isolate KMS24 was able to survive better under a greater variety of environmental conditions. Both strains were therefore suitable to use for further investigating their abilities to remediate water contaminated with HMs and Na

Effects of 5-aminolevulinic acid (ALA)-containing supernatants from selected Rhodopseudomonas palustris strains on rice growth under NaCl stress, with mediating effects on chlorophyll, photosynthetic electron transport and antioxidative enzymes

Background: Rice is globally one of the most important food crops, and NaCl stress is a key factor reducing rice yield. Amelioration of NaCl stress was assessed by determining the growth of rice seedlings treated with culture supernatants containing 5-aminolevulinic acid (ALA) secreted by strains of Rhodopseudomonas palustris (TN114 and PP803) and compared to the effects of synthetic ALA (positive control) and no ALA content (negative control). Results: The relative root growth of rice seedlings was determined under NaCl stress (50 mM NaCl), after 21 d of pretreatment. Pretreatments with 1 \u3bcM commercial ALA and 10X diluted culture supernatant of strain TN114 (2.57 \u3bcM ALA) gave significantly better growth than 10X diluted PP803 supernatant (2.11 \u3bcM ALA). Rice growth measured by dryweight under NaCl stress ordered the pretreatments as: commercial ALA > TN114 > PP803 > negative control. NaCl stress strongly decreased total chlorophyll of the plants that correlated with non-photochemical quenching of fluorescence (NPQ). The salt stress also strongly increased hydrogen peroxide (H2O2) concentration in NaCl-stressed plants. The pretreatments were ordered by reduction in H2O2 content underNaCl stress as: commercial ALA > TN114 > PP803 > negative control. The ALA pretreatments incurred remarkable increases of total chlorophyll and antioxidative activities of catalase (CAT), ascorbate peroxide (APx), glutathione reductase (GR) and superoxide dismutase (SOD); under NaCl stress commercial ALA and TN114 had generally stronger effects than PP803. Conclusions: The strain TN114 has potential as a plant growth stimulating bacterium that might enhance rice growth in saline paddy fields at a lower cost than commercial ALA