Improving dryland maize productivity and water efficiency with heterotrophic ammonia-oxidizing bacteria via nitrification and cytokinin activity

A two-year field experiment conducted under dryland conditions in semi-humid and drought-prone regions of China aimed to assess the effect of ammonia-oxidizing bacterial on maize water use efficiency and yield.A heterotrophic ammonia-oxidizing bacteria(HAOB)strain S2_8_1 was used.Six treatments were applied:(1)no irrigation+HAOB strain(DI),(2)no irrigation+blank culture medium(DM),(3)no irrigation control(DCK),(4)irrigation+HAOB(WI),(5)irrigation+blank culture medium(WM),and(6)irrigation control(WCK).Results revealed that HAOB treatment increased maize growth,yield,and water use efficiency over controls,regardless of whether the year was wet or dry.This improvement was attributed to the accelerated nitrification in the rhizosphere soil due to HAOB inoculation,which subsequently led to increased levels of leaf cytokinins.Overall,these findings suggest that HAOB inoculation holds promise as a strategy to boost water use efficiency and maize productivity in dryland agriculture.

Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

Bioleaching of heavy metals from contaminated alkaline sediment by auto- and heterotrophic bacteria in stirred tank reactor

Bioleaching Xiangjiang River alkaline sediment contaminated by multiple heavy metals was investigated. Multiple metals in alkaline sediment possess significant toxicity to aquatic organisms or humans and will greatly inhibit bioleaching. The bioleaching method using autotrophic bacteria mixed with heterotrophic bacteria can solve this problem successfully. The experiment results showed that bioleaching efficiencies of Zn, Mn, Cu, and Cd were 95.2 %, 94.2 %, 90.1 %, and 84.4 %, respectively. Moreover, the changes of heavy metal concentrations in different fractions in contaminated sediment before and after bioleaching were analyzed by selective sequential extraction, and it was discovered that the main fractions of Zn, Mn, Cu and Cd after bioleaching are Fe-Mn oxide, organic associated form and a residual form. Its biotoxicity decreased greatly. The bioleaching heavy metals from sediment using autotrophic bacteria combined with heterotrophic bacteria can effectively improve the bioleaching efficiency and reduce toxicity.

秋季东、黄海异养细菌(Heterotrophic Bacteria)的分布特点

20 0 0年 1 0— 1 1月 ,乘“北斗号”考察船进行秋季“东、黄海生态系统动力学与生物资源可持续利用”大面调查 ,研究秋季东、黄海异养细菌的分布。结果表明 ,异养细菌在黄海和东海的丰度分别在 (2 .3 7— 1 3 .3 3 )× 1 0 8cell/L和 (3 .0 5— 1 3 .6 2 )× 1 0 8cell/L之间。细菌丰度最高值出现在长江口附近 ,且断面E和断面F各站位的细菌丰度明显高于其他断面。异养细菌丰度大小以长江口为中心向外海依次递减。东、黄海水体异养细菌生物量分别在 2 4 4 .45—1 81 2 .90mgC/m2 和 1 0 0 .6 0— 940 .87mgC/m2 之间。东、黄海异养细菌丰度无显著差异 ,但是东海海域水体异养细菌生物量高于黄海海域。异养细菌空间分布与浮游植物叶绿素在东海有一定的相关性 。

Soil heterotrophic respiration in Casuarina equisetifolia plantation at different stand ages

The soil respiration rates （Rh） in 6-year-old （young）, 17-year-old （middle-age）, 31-year-old （mature） Casuarina equisetifolia coastal plantations were measured using an LICOR-8100 automated soil CO2 flux system from May 2006 to April 2007. Results show that Rh displayed an obvious seasonal pattern across the observed years. The maximum values of Rh occurred at June and July and the minimum at December and January. Soil temperature and soil moisture as well as their interaction had significant effects on the monthly dynamics of Rh. The analysis by one-way ANOVA showed that Rh had a significantly exponential relation （p〈0.05） to soil temperature at soil depth of 5 cm, and had a linear relation （p〈0.05） to soil water content of the upper 20 cm. The result estimated by the two-factor model shows that soil temperature at soil depth of 5 cm and soil moisture at soil depth of 20 cm could explain 68.9%-91.9% of seasonal variations in Rh. The or- der of Rh rates between different stand ages was middle-age plantation〉mature plantation〉young-age plantation. With the increase of growth age of plantation, the Q10 of Rh increased. The contribution of Rh to total soil surface CO2 flux was 71.89%, 71.02% and 73.53% for the young, middle-age and mature plantation, respectively. It was estimated that the annual CO2 fluxes from Rh were 29.07, 38.964 and 30.530 t.ha^-1.a^-1 for the young, middle-age and mature plantation, respectively.

Discussion on Problem of Fermentation Contamination of Heterotrophic Chlorella

The contamination reasons were analyzed form the viewpoints of strain preparation, air system, medium and equipment sterilization and pipeline configura- tion. Moreover, the contamination-preventing measures were defined. We also sum- marized the characteristics of bacteria that contaminated the fermentation, as well as checking methods and remedial measures.

Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium （NH4^＋-N）. In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at different carbon to nitrogen （C/N） mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions （C/N 10, 30℃, 120 r/min）, YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine （NHzOH）, nitrite （NO2^-） and nitrate （NO3^-） as well as the denitrification product, nitrogen gas （N2）, were detected under completely aerobic conditions.

Effect of ultraviolet mutagenesis on heterotrophic strain mutation and bioleaching of low grade copper ore

The effect of ultraviolet mutagenesis on a heterotrophic strain(Providencia JAT-1) mutation was studied and bioleaching of low grade copper ore with mutant bacteria was investigated. The results show that the activity of bacteria was improved after ultraviolet mutagenesis; the best irradiation time was 120 s. Compared to the original bacteria, the cells density of mutant bacteria at stationary phase increased by 26% and ammonia produced by mutant bacteria increased by 12%. Higher activity of bacteria leads to a higher copper extraction rate. The bioleaching performance of Providencia JAT-1 was improved after UV mutagenesis. The copper extraction rate with mutant bacteria increased by 10.6% compared to the original bacteria. The ore surface was corroded and the fine particles were absent after bioleaching. Free copper oxide and copper silicates could be leached out easily by using JAT-1; a small part of the copper sulfide can also be leached out. Bioleaching using JAT-1 is more effective than ammonia leaching and copper extraction rate with mutant bacteria was 21.1% higher than that by ammonia leaching under the same condition.

Purification and Characterization of a Low-temperature Hydroxylamine Oxidase from Heterotrophic Nitrifier Acinetobacter sp.Y16

Objective To purify a low-temperature hydroxylamine oxidase （HAO） from a heterotrophic nitrifying bacterium Acinetobacter sp. Y26 and investigate the enzyme property. Methods A HAO was purified by an anion-exchange and gel-filtration chromatography from strain Y16. The purity and molecular mass were determined by RP-HPLC and SDS-PAGE. The HAO activity was detected by monitoring the reduction of potassium ferricyanide using hydroxylamine as substrate and ferricyanide as electron acceptor. The partial amino acid sequence was determined by mass spectrometry. Results The low-temperature HAO with a molecular mass of 61 kDa was purified from strain Y26 by an anion-exchange and gel-filtration chromatography. The enzyme exhibited an ability to oxidize hydroxylamine in wide temperature range （4-40 ℃） in vitro using hydroxylamine as substrate and ferricyanide as electron acceptor. It was stable in the temperature range of 4 to 25 ℃ and pH range of 6.0 to 8.5 with less than 30% change in its activity. The optimal temperature and pH were 15 ℃ and 7.5, respectively. Three peptides were determined by mass spectrometry which were shown to be not identical to other reported HAOs. Conclusion This is the first study to purify a low-temperature HAO from a heterotrophic nitrifier Acinetobecter sp. It differs from other reported HAOs in molecular mass and enzyme properties. The findings of the present study have suggested that the strain Y26 passes through a hydroxylamine-oxidizing process catalyzed by a low-temperature HAO for ammonium removal.

Isolation and characterization of heterotrophic nitrifying bacteria in MBR

The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. Continuous tests via a membrane bioreactor (MBR) were operated under the controlled conditions to proliferate the nitrifiers. Heterotrophic nitrifying bacteria were isolated from the system in which the efficiency of total nitrogen(TN) removal was up to 80%. Since no autotrophic ammonium and nitrite oxidizers could be detected by fluorescence in situ hybridization(FISH), oxidized-N production was unlikely to be catalyzed by autotrophic nitrifiers during the heterotrophic nitrifiers' isolation in this study. The batch test results indicate that the isolated heterotrophic bacteria were able to nitrify. After 3 weeks incubation, the efficiencies of the COD removal by the three isolated bacterial strains B1, B2, and B3 were 52 6%, 71 7%, and 77 7%, respectively. The efficiencies of the TN removal by B1, B2, and B3 were 35 6%, 61 2% and 68 7%, respectively.

Enhanced biological nutrient removal by the alliance of a heterotrophic nitrifying strain with a nitrogen removing ecosystem

Nitrogen removal from synthetic wastewater was investigated in an airlift bioreactor （ALB）, augmented with a novel heterotrophic nitrifier Pseudonocardia ammonioxydans H9^T under organic carbon to nitrogen ratios （Corg/N） ranging from 0 to 12. Effect of the inoculated strain was also determined on the settling properties and the removal of chemical oxygen demand （COD）. Two laboratory scale reactors were set up to achieve a stable nitrifying state under the same physicochemical conditions of hydraulic retention time （HRT）, temperature, pH and dissolved oxygen （DO）, and operated under the sequencing batch mode. The level of DO was kept at 0.5- 1.5 mg/L by periodic stirring and aeration. Each specific Corg/N ratio was continued for duration of 3 weeks. One of the reactors （BR2） was inoculated with P ammonioxydans H9^T periodically at the start of each Corg/N ratio. Sludge volumetric index （SVI） improved with the increasing Corg/N ratio, but no significant difference was detected between the two reactors. BR2 showed higher levels of nitrogen removal with the increasing heterotrophic conditions, and the ammonia removal reached to the level of 82%-88%, up to10% higher than that in the control reactor （BR1） at Corg/N ratios higher than 6; however, the ammonia removal level in experimental reactor was up to 8% lower than that in control reactor at Corg/N ratios lower than 2. The COD removal efficiency progressively increased with the increasing Corg/N ratios in both of the reactors. The COD removal percentage up to peak values of 88%-94% in BR2, up to 11% higher than that in BR1 at Corg/N ratio higher than 4. The peak values of ammonia and COD removal almost coincided with the highest number （18%-27% to total bacterial number） of the exogenous bacterium in the BR2, detected as colony forming units （CFU）. Furthermore, the removal of ammonia and COD in BR2 was closely related to the number of the inoculated strain with a coefficient index （R2） up to 0.82 and 0.85 for ammonia and COD, respectively. These results suggest that it was more efficient for both the ammonia and carbon nutrient removals in a reactor inoculated with a heterotrophic nitrifier at high Corg/N ratio, inferring that the heterotrophic nitrifers would be practically more available in the treatment of wastewater with high level of ammonia and COD.

Distribution, residence time, autotrophic production, and heterotrophic removal of DOP in the Mirs Bay, northern South China Sea

The importance of dissolved organic phosphorus(DOP) as a potential nutrient source for primary producers in marine systems has been recognized for up to eight decades, but currently, the understanding of the biogeochemistry of DOP is in its infancy. In the present study, monthly data between 2000 and 2014 were used to analyze the temporal and spatial distributions of DOP in the Mir Bay, the northern South China Sea. The DOP residence time(TDOP) was also investigated using a simple regression analysis in combination with chlorophyll a(Chl a) measurements while excess DOP(ΔDOP), produced by the biogeochemical processes of autotrophic production and heterotrophic removal, was determined using a two-component mixing mass-balance model in combination with salinity measurements. The results showed that the DOP concentration was(0.017±0.010) mg/L higher in the surface-water compared with the bottom-water and higher in the inner Tolo Harbour and waters adjacent to Shatoujiao compared with the main zone of the bay. Although seasonal changes and annual variability in the DOP were small, the surface DOP concentration was higher in the wet season(April–September)than in the dry season(October–March) due to the impacts of seaward discharges and atmospheric deposition into the bay. Measurement and regression results showed that the DOP release rate from phytoplankton production was about 1.83(gP)/(gChl a) and the TDOP was about 7 d, which implied that the DOP cycle in the bay was rapid. The ΔDOP was calculated from the model to be about 0.000 mg/L in the main zone of the bay and about 0.002 mg/L in the inner Tolo Harbour and waters adjacent to Shaotoujiao, suggesting that the autotrophic production of DOP was almost balanced by the heterotrophic removal in the main zone of the bay and dominated in the inner Tolo Harbour and waters adjacent to Shaotoujiao. In conclusion, the Mirs Bay is very productive and fairly heterotrophic.

Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature

The abundance of general aerobic heterotrophic bacteria(GAB) from the water and sediment in the Bering Sea and the Chukchi Sea was determined by using petri dish cultivation and counting method. The abundance of GAB among the different sea areas, sampling sites, layers of sediments surveyed and adaptability to differential temperatures was studied. The result obtained showed that: the occurrence percentage of GAB in the surface water was higher than that in sediment, but the abundance was only 0.17% of sediment. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage, abundance and its variation of GAB in the Bering Sea were higher than that in the Chukchi Sea respectively. The average value of the abundance in the all sediment surveyed was 3166.3×10 2 CFU·g -1(wet.). The abundance of GAB in sediment showed a trend: roughly higher in the lower latitudinal area than higher latitude. The results from temperature test mean that: the majority of bacteria tested were cold-adapted ones, minority might be mesophilic bacteria. The results indicated that, Arctic ocean bacteria had a stronger adaptability to environmental temperature.

Hydrobiological variables as a regulatory factor on the abundance of heterotrophic flagellates in an urban pond

The seasonal abundance of flagellates has been monitored over a period of 1 year from December 2013 to November 2014(divided into 4 conjugative seasons namely winter,spring,summer,and autumn)in an experimental pond located in Rajshahi City Corporation area,Bangladesh.To our knowledge,this study is the fi rst to shed light on the occurrence and possible interrelationships among heterotrophic flagellates(HF),bacteria and zooplankton in Bangladesh and the result obtained by this study will be beneficial for similar water ecosystem all over the world.Standard methods were used to determine the prescribed hydrological parameters and zooplankton cell density.Maximum HF abundance(14 346.00 cells/mL)was found in the spring and the minimum(5 215.00 cells/mL)occurred in the summer.Inverse to HF,significantly(P<0.05)higher zooplankton abundance was found during the winter(782.00±47.62 cells/mL)and the lowest value was found in the autumn(448.00±39.15 cells/mL).Whereas similar to the HF,total bacterial abundance was significantly higher during the spring((2.25±1.05)×10^5 cells/mL)and lower in the summer((0.79±0.06)×10^5 cells/mL).Multivariate analyses(ANOSIM and MDS)have shown significant seasonal differences for cell numbers where MDS ordination plot and cluster analysis based on similarity in the genera abundance of HF revealed overlapping condition between winter and spring.Canonical correspondence analysis(CCA)also showed a distinct separation among the genera based on the prevailing hydrological situation and indicated that temperature,pH,BOD5,and NO3^-were the most important environmental variables in determining the observed variation in HF community structure.Among the biological factors,zooplankton showed negative but total bacteria were positively correlated with HF abundance.

Terrestrial dissolved organic carbon consumption by heterotrophic bacterioplankton in the Huanghe River estuary during water and sediment regulation

Nearly 20%–50% of the annual terrestrial dissolved organic carbon(DOC)from the Huanghe(Yellow)River was transported to the estuary during the 5-14d of water and sediment regulation.The concentration of DOC increased sharply during the period of water and sediment regulation,which may promote the terrestrial DOC consumption by heterotrophic bacterioplankton.Water and sediment regulation provides an ideal condition for the study of terrestrial DOC consumption by heterotrophic bacterioplankton when terrestrial DOC increases sharply in rainy season,which may help to seek the fates of terrestrial DOC in the estuaries and coasts.In this study,the concentration and stable isotope of DOC,the biomass,growth,and respiration of heterotrophic bacterioplankton were determined.By the study,we found both average percent contribution of terrestrial DOC to the DOC pool and Contribution of terrestrial DOC to the carbon composition of heterotrophic bacterioplankton decreased as distance from the river mouth increased off shore,which was deceased from(39.2±4.0)%,(37.5±4.3)%to(30.3±3.9)%,(28.2±3.9)%respectively.255-484μg C/(L·d)terrestrial DOC was consumed by heterotrophic bacterioplankton.And 29%-45%terrestrial DOC consumed by heterotrophic bacterioplankton releasing as CO2 by respiration.Comparing with tropical estuary,terrestrial DOC consumed by heterotrophic bacterioplankton was lower in temperate estuary(this study).Temperature may limit the consumption of terrestrial DOC by heterotrophic bacterioplankton.

Heterotrophic bacteria of the Dapeng Bay in the South China Sea: community structure,abundance,and the relationships of culturablity with environmental factors

The community composition,abundance and culturablity of heterotrophic bacterioplankton in the Dapeng Bay of the South China Sea were investigated by morphological method,bacterial cultivation and biochemical methods over an annual cycle.Aeromonas and Pseudomonas were the predominant genera among the Gram-negative bacteria.The bacterioplankton abundance fluctuated from 2.07×10 8 to 2.44×10 9 cells/dm 3 ,and culturable bacteria abundance ranged between 0.1×10 6 and 16.07×10 6 CFU/dm 3 .The Culturablity of heterotrophic bacteria ranged between 0.01% and 1.31%.The relationship between bacterial culturablity and the environmental factors was also studied in different sites of the Dapeng Bay.Throughout the bay,a significantly positive relationship was evidenced between bacterial culturability and temperature,meanswhile bacterial culturability was significantly inversely related with salinity.The positive relationship was shown at the central bay while a negative relationship was observed at the bay mouth and there was no significant correlation at top bay between bacterial culturablity and chlorophyll a of sea water.A positive relationship was found between culturability and DIN all the bay,but DIP showed a significantly negative relationship with bacterial culturability only at the mouth of the bay.

Isolation and Characterization of a New Heterotrophic Nitrifying Bacillus sp. Strain

Objective To characterize the heterotrophic nitrifying bacteria. Methods The bacteria were isolated from membrane bioreactor for treating synthetic wastewater using the method newly introduced in this study. Fluorescence in situ hybridization （FISH） was used to validate the nonexistence of autotrophic ammonia oxidizers and nitrite oxidizers. Batch tests were carried out to investigate the capability of heterotrophic nitrification by the pure culture. Phylogenetic analysis of the pure culture was performed. Results A heterotrophic nitrifier, named Bacillus sp. LY, was newly isolated from the membrane bioreactor system in which the efficiency of TN removal was up to 80%. After 24-day, incubation, the removal efficiency of COD by Bacillus sp. LY was 71.7 %. The ammonium nitrogen removal rate after assimilation nearly ceased by Bacillus sp. LY was 74.7% The phylogenetic tree of Bacillus sp. LY and the neighbouring nitrifiers were given. Conclusions The batch test results indicate that Bacillus sp. LY can utilize the organic carbon as the source of assimilation when it grows on glucose and ammonium chloride medium accompanying the formation of oxidized-nitrogen. It also can denitrify nitrate while nitrifying. Bacillus sp. LY may become a new bacterial resource for heterotrophic nitrification and play a bioremediation role in nutrient removal.

Isolation and Characterization of Heterotrophic Nitrifying Strain W1

In a high concentration substrate medium, a heterotrophic bacterium with high removal efficiency of ammonium, named W1, was isolated from activated sludge of coking wastewater treatment facility. The bacterium was Gram-negative, rod-shaped, and identified preliminarily as Alcaligenes sp. according to its morphological and physiological properties and its 16S rRNA gene sequence analysis. In the high concentration ammonium medium (400 mg·L 1 4 NH -N), the effects of C source, N source, C/N ratio and initial pH of medium on ammonium removal were investigated in order to determine the optimal condition for strain W1. The maximum ammonium removal was around 95% in 4 days in an improved medium. The production of N 2 gas was examined in a closed system that was full of pure oxygen at the beginning. N 2 gas was detected in the system after 4 days of cultivation, which further testified that strain W1 has heterotrophic nitrification and aerobic denitrification abilities simultaneously.

Nitrogen removal characteristics of heterotrophic nitrification-aerobic denitrification by Alcaligenes faecalis C16

Alcaligenes faecalis C16 was found to have the ability to heterotrophically nitrify and aerobically denitrify. In order to further understand its nitrogen removal ability and mechanism, the growth and ammonium removal response were investigated at different C/N ratios and ammonium concentrations in the medium with citrate and acetate as carbon source separately. Furthermore, experiments of nitrogen sources, production of nitrogen gas and enzyme assay were conducted. Results show that the bacterium converts NH+4-N and produces NH2 OH during the growing phase and nitrite accumulation is its distinct metabolic feature. A. faecalis C16 is able to tolerate not only high ammonium concentration but also high C/N ratio, and the ammonium tolerance is associated with carbon source and C/N ratio. The nitrogen balance under different conditions shows that approximately28%–45% of the initial ammonium is assimilated into the cells, 44%–60% is denitrified and several percent is converted to nitrification products. A. faecalis C16 cannot utilize hydroxylamine, nitrite or nitrate as the sole nitrogen source for growth. However, nitrate can be used when ammonium is simultaneously present in the medium. A possible pathway for nitrogen removal by C16 is suggested. The preliminary enzyme assay provides more evidence for this nitrogen removal pathway.

Study on Characteristics of a Strain of Penicillium sp.Capable of Heterotrophic Ammonium Oxidation

An ammonia-oxidizing strain of Penicillium sp., M25-22 which was isolated from chicken feces compost, was studied to make clear its characteristics of ammonium oxidation and provide references for its application in aerobic composting. In media containing （NH4）2SO4 at a concentration of 0.5 g 100 mL^-1, mycelium weight and utilization ratio of ammonium nitrogen increased markedly during the 1st 5 d, concentration of nitrate increased markedly from the 3rd to the 5th d and concentration of nitrite remained at a low level. The strain showed the ability to oxidize ammonium nitrogen growing in media containing glucose, sucrose, starch, or cellulose as the sole carbon source and to oxidize the negative trivalent nitrogen of ammonium sulfate, peptone, acetamide, urea, or L-aspartate. Slowly available carbon or nitrogen sources such as starch, cellulose, and peptone were beneficial to ammonium oxidation. In media containing sucrose as the sole carbon source and ammonium sulfate as the sole nitrogen source, nitrate formation was the most pronounced with sucrose present at a concentration of 12 g L^-1 and ammonium nitrogen present at a concentration of 2.438 mg mL% at the initial pH level of 7.5 and at 30℃.