Biodegradation of Terephthalic Acid by Isolated Active Sludge Microorganisms and Monitoring of Bacteria in a Continuous Stirred Tank Reactor

Abstract Terephthalic acid is extensively used as an important raw material in polyester fibers, as well as the production of polyethylene terephthalate bottles and textile industries. Especially, in the petrochemical industry, toxic chemicals are released to the atmosphere during the production of polyethylene terephthalate, unless the wastewater treatment is carried out. It's a well-known fact that chemicals have serious side effects on human health, so manufacturing companies should not dispose of such harmful chemicals without treatment. Biodegradation is an effective option for eco-friendly degradation of hydrocarbons. Hydrocarbon-degrading bacteria are everywhere in environment and can utilize these chemicals as sources of carbon and energy. In the present study, aerobic bacterial strains T1, T4, T5, and TK were isolated from activated sludge and crude oil deposits of a petrochemical company in Turkey. The strains were identified to be Pseudomonas sp., Chryseobacterium sp., Burkholderia sp., and Arthrobacter sp. according to morphological, physiological and biochemical characteristics. The strains were able to degrade about 100% of 100 mg/L terephthalic acid within, respectively, 8, 67, 52, 24 hour as sole carbon and energy source. Therefore, these isolates can be effectively used for degradation of terephthalic acid contaminated sites. In addition to this, a Continuous Stirred Tank Reactor (CSTR) was used to test the biodegradation capabilities of the isolates in the activated sludge system. Throughout the biodegradation, bacterial existence and numbers were monitored using designed primer-probe sets in real-time polymerase chain reaction (PCR).

Purified Terephthalic Acid Wastewater Treatment Using Modified Two-Stage UASB Bioreactor Systems.

Microbial community dynamics and PTA wastewater degradation performance of sequentially connected two-stage upflow anaerobic sludge blanket (UASB) bioreactors have been studied for 225 days. The working volume of acidogenic (R1) and methanogenic reactors (R2) have sixfold differences. Thus, the reactors operated under different hydraulic retention time (HRT) conditions, which are preferential for PTA wastewater content. Archeal and bacterial profiles of granules were analyzed with denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR (Q-PCR) techniques. According to high-pressure liquid chromatography (HPLC) results, 4-Carboxybenzaldehyde (4-CBA) and acetic acid (AA) completely degraded in the first stage, whereas terephthalate (TA) and p-toluic acid (p-TA) degradation ratios were 90% and 47% in the second stage, respectively. The methane content of the UASB reactor was determined as 76% by gas chromatography (GC) analysis. Microbial community analysis indicated that the members of hydrogenotrophic methanogen groups Methanobacteriales and Methanomicrobiales were dominantly responsible for methane production throughout the process.

Bacterial and archeal dynamics of a labscale HYBRID gas fermentation bioreactor fed with CO2 and H2.

16s rDNA-based methods were used in order to identify the dynamics of microbial profiles in a HYBRID gas fermentation bio-methanization reactor. The effects of various H2 and CO2 ratios on microbial community were investigated. The HYBRID gas fermentation reactor was composed of granular anaerobic seed and the system fed with only H2 and CO2 gases. No additional organic material and trace element was fed during the throughout the experiments; thus, the microbial diversity was directly related to production of methane. The dynamics of the microbial communities were investigated with DGGE and real-time PCR analysis. The results showed that Methanobacteriales members were more dominated than Methanosarcinales and Methanomicrobiales members in the system. DGGE results indicated that Methanosaeta concilii, Methanoculleus sp., Methanosphaerula palustris, Methanofollis formosanus, Methanolinea sp., and Methanobacterium palustre were the most prominent methanogens depending on different H2/CO2 ratios. DGGE profiles suggested that hydrogenotrophic and acetoclastic species were responsible for the production of methane. The survival of syntrophic bacteria and acetoclastic methanogens was attributed to their utilization of organic materials provided by lysis. To the best of our knowledge, this is the first microbial profile detection study in a hybrid bioreactor system operated with only pure hydrogen and carbon dioxide.

CO2 utilization via a novel anaerobic bioprocess configuration with simulated gas mixture and real stack gas samples.

CO2, which is considered to be one of the major causes of climate change, has reached to critical levels in the atmosphere due to tremendous consumption of fossil fuels all over the world. In this study, anaerobic bioconversion of CO2 into bio-methane using a novel bioprocess configuration (HYBRID bioreactor) was studied under mesophilic conditions. Varying ratios of H2/CO2 gas mixture and volumetric feeding rates were investigated and no additional organic matter and trace element were needed throughout the study. The maximum methane production of 19 m3 CH4/m3 reactor/d was achieved at a H2/CO2 ratio of 4:1 and feeding rate of 24 m3 gas/m3 reactor/d. It was determined that H2 conversion rate is about 96%. For demonstration purpose, real stack gas sample from a petrochemical industry was also tested under optimized operational conditions. No inhibitory effect from stack gas mixture was observed. This study provided an environmentally friendly and sustainable solution for industries such as petrochemical industry in order to produce extra energy while capturing their waste CO2. Thereby, a sustainable and environmentally friendly model solution was presented for industries with high CO2 emissions.

Determination of the microbial flora in traditional Izmir Tulum cheeses by Denaturing Gradient Gel Electrophoresis.

In this study, it was aimed to determine microbial flora members in three traditional Tulum cheeses (C1, C2 and C3) produced in different villages and settlement areas in Izmir, Turkey. For this purpose, culture depended and 16S rRNA based culture independent methods were used. According to the results of culture depended method, Lactococcus spp., Enterococcus spp., Staphylococcus spp., Lactobacillus spp., Pediococcus spp. and yeast-mold were detected in all samples at different levels. In order to determine and identify both of the culturable and non-culturable microorganisms, denaturing gradient gel electrophoresis (DGGE) method was used. DGGE results have shown that there were eight different dominant microorganisms (Streptococcus thermophilus, Lactococcus lactis subs. lactis, Streptococcus infantarius subs. infantarius, Lactobacillus gallinarum, Streptococcus equinus, Enterococcus faecalis, Enterococcus faecium, Lactococcus garvieae) in three regionally cheese samples. Further more, total bacterial loads were monitored with real-time PCR (qPCR) method. According to the results, 3.5 × 108, 3.8 × 108, 8.4 × 108 copy number of DNA was detected in C1, C2 and C3 cheese samples, respectively. This study is the first description for the dynamics of microbial composition of Izmir Tulum cheese after the production and brining processes.

Midgut Bacterial Diversity of Wild Populations of Phlebotomus (P.) papatasi, the Vector of Zoonotic Cutaneous Leishmaniasis (ZCL) in Turkey.

Phlebotomine sand flies are hematophagous insects that harbor bacterial, viral and parasitic agents like Bartonella sp., Phleboviruses and Leishmania spp., respectively. There are few reports on bacterial microbiota of Phlebotomus (P.) papatasi but no data available for natural populations of Turkey, where leishmaniasis is endemic. Therefore, we aimed to investigate the midgut bacterial flora of different populations of P. papatasi. Sand flies were collected from different towns (Karaburun, Urla, Ayvacik and Basçayir) located in the western part of Turkey. Laboratory reared P. papatasi were included in the study as an insectarium population. After sterile washing steps, sand flies were dissected and guts were separated. Three pools, (males, unfed females and blood-fed females) were generated for each population. Prokaryotic 16 S rRNA gene was amplified and DGGE was performed. Fourteen different organisms belonging to two Phylum (Proteobactericea and Furmicutes) were identified according to sequence results in the studied pools. The presence of Wolbachia sp. was shown for the first time in the wild-caught sand fly populations of Turkey. This is the first report of gut bacterial flora of wild-caught P. papatasi collected in an endemic area for leishmaniasis in Turkey. Microbiome profiling of wild-caught sand flies will be of great help in the investigating of possible vector control candidates for paratransgenic control approach.