Synergistic impact of sonic-tenside on biomass disintegration potential: Acidogenic and methane potential studies, kinetics and cost analytics.

An exploration into the symbiotic impact of sonic-tenside (SDBS - sodium dodecyl benzene sulfonate) on biomass disintegration potential and to reduce the energy consumption was studied. At optimized condition (specific energy input 9600 kJ/kg TS; SDBS dosage 0.07 g/g SS), higher percentage of biomass lysis and solids reduction (23.9% and 19.8%) was obtained in blended sonic-tenside disintegration (STD), than sonic disintegration (SD) (17.6% and 9.8%). The bioacidogenic potential (BAP) assay in terms of volatile fatty acids (VFA) production (722 mg/L) was found to be higher for STD, in comparison to SD (350 mg/L). The impact of STD on anaerobic digestion was evident from its methane yield (0.239 g/g COD), higher than SD (0.182 g/g COD). A monetary evaluation of the present study provides a net gain of 2 USD/ton for STD, indicating the profitability of the technique.

Energy-efficient methane production from macroalgal biomass through chemo disperser liquefaction.

In this study, an effort has been made to reduce the energy cost of liquefaction by coupling a mechanical disperser with a chemical (sodium tripolyphosphate). In terms of the cost and specific energy demand of liquefaction, the algal biomass disintegrated at 12,000rpm for 30min, and an STPP dosage of about 0.04g/gCOD was chosen as an optimal parameter. Chemo disperser liquefaction (CDL) was found to be energetically and economically sustainable in terms of liquefaction, methane production, and net profit (15%, 0.14gCOD/gCOD, and 4 USD/Ton of algal biomass) and preferable to disperser liquefaction (DL) (10%, 0.11 gCOD/gCOD, and -475 USD/Ton of algal biomass).

Biodegradation of polycyclic aromatic hydrocarbons by an acidophilic Stenotrophomonas maltophilia strain AJH1 isolated from a mineral mining site in Saudi Arabia.

The present study aims at analyzing the degradation of polycyclic aromatic hydrocarbons (PAHs) at acidic conditions (pH = 2) by acidophilic Stenotrophomonas maltophilia strain AJH1 (KU664513). The strain AJH1 was obtained from an enrichment culture obtained from soil samples of mining area in the presence of PAH as sole sources of carbon and energy. Strain AJH1was able to degrade low (anthracene, phenanthrene, naphthalene, fluorene) and high (pyrene, benzo(e)pyrene and benzo(k)fluoranthene) molecular weight PAHs in acidophilic mineral salt medium at pH 2, with removal rates of up to 95% (LMW PAH) and 80% (HMW PAH), respectively. In addition, strain AJH1 treated petroleum wastewater with 89 ± 1.1% COD removal under acidic condition (pH 2) in a continuously stirred reactor. Acidophilic S. maltophilia strain AJH1, hence holds the promise as an effective degrader for biological treatment of PAHs contaminated wastewater at acidic pH.

Treatment of seafood processing wastewater using upflow microbial fuel cell for power generation and identification of bacterial community in anodic biofilm.

Tubular upflow microbial fuel cell (MFC) utilizing sea food processing wastewater was evaluated for wastewater treatment efficiency and power generation. At an organic loading rate (OLR) of 0.6 g d(-1), the MFC accomplished total and soluble chemical oxygen demand (COD) removal of 83 and 95%, respectively. A maximum power density of 105 mW m(-2) (2.21 W m(-3)) was achieved at an OLR of 2.57 g d(-1). The predominant bacterial communities of anode biofilm were identified as RB1A (LC035455), RB1B (LC035456), RB1C (LC035457) and RB1E (LC035458). All the four strains belonged to genera Stenotrophomonas. The results of the study reaffirms that the seafood processing wastewater can be treated in an upflow MFC for simultaneous power generation and wastewater treatment.

Co-metabolic degradation of benzo(e)pyrene by halophilic bacterial consortium at different saline conditions.

Polyaromatic hydrocarbons (PAHs) with high molecular weight (more than three benzene rings) were difficult to degrade in saline environment. The present study details about the bacterial consortium enriched from industrial sludge from salt manufacturing company, Tuticorin, Tamilnadu (India), which was capable of degrading 1, 4 dioxane (Emerging micropollutant) and also phenanthrene as sole carbon source under saline condition. The halophilic bacterial consortium was able to degrade low molecular weight (LMW) phenanthrene, but unable to degrade high molecular weight (HMW) benzo(e)pyrene. To overcome this problem, phenanthrene was added as co-substrate along with benzo(e)pyrene which enhanced the biodegradation process by co-metabolism under saline conditions. The consortium potentially degraded 80% and 99% of benzo(e)pyrene in 7 days and phenanthrene in 5 days at 30 g l⁻¹ of NaCl concentration. When the saline concentration increased to 60 g l⁻¹, degradation of phenanthrene (97% in 8 days) and benzo(e)pyrene (65% in 10 days) was observed. Further increase in saline concentration to 90 g I⁻¹ of NaCI showed reduction in the percent degradation of phenanthrene and benzo(e)pyrene leads to 30.3% and 9% respectively in 6 days. Potential bacterial strains, present in PAHs degrading bacterial consortium were identified as Achromobacter sp. AYS3 (JQ419751), Marinobacter sp. AYS4 (JQ419752) and Rhodanobacter sp. AYS5 (JQ419753). The present study details about the effect of salinity on PAHs degradation and vital role of co-metabolism on biodegradation of benzo(e)pyrene with phenanthrene under saline conditions.

Enzymatic bioremediation of polyaromatic hydrocarbons by fungal consortia enriched from petroleum contaminated soil and oil seeds.

The present study focuses on fungal strains capable of secreting extracellular enzymes by utilizing hydrocarbons present in the contaminated soil. Fungal strains were enriched from petroleum hydrocarbons contaminated soil samples collected from Chennai city, India. The potential fungi were isolated and screened for their enzyme secretion such as lipase, laccase, peroxidase and protease and also evaluated fungal enzyme mediated PAHs degradation. Total, 21 potential PAHs degrading fungi were isolated from PAHs contaminated soil, which belongs to 9 genera such as Aspergillus, Curvularia, Drechslera, Fusarium, Lasiodiplodia, Mucor Penicillium, Rhizopus, Trichoderma, and two oilseed-associated fungal genera such as Colletotrichum and Lasiodiplodia were used to test their efficacy in degradation of PAHs in polluted soil. Maximum lipase production was obtained with P. chrysogenum, M. racemosus and L. theobromae VBE1 under optimized cultural condition, which utilized PAHs in contaminated soil as sole carbon source. Fungal strains, P. chrysogenum, M. racemosus and L. theobromae VBE1, as consortia, used in the present study were capable of degrading branched alkane isoprenoids such as pristine (C17) and pyrene (C18) present in PAHs contaminated soil with high lipase production. The fungal consortia acts as potential candidate for bioremediation of PAHs contaminated environments.

Biodegradation of polycyclic aromatic hydrocarbons by a halotolerant bacterial strain Ochrobactrum sp. VA1.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in the environment and are derived from both man-made and natural resources. The present study is focused on the degradation of PAHs by a halotolerant bacterial strain under saline conditions. The bacterial strain VA1 was isolated from a PAH-degrading consortium that was enriched from marine water samples that were collected from different sites at Chennai, India. In the present study, a clearing zone formed on PAH-amended mineral salt agar media confirmed the utilization of PAH by the bacterial strain VA1. The results show that the strain VA1 was able to degrade anthracene (88%), phenanthrene (98%), naphthalene (90%), fluorene (97%), pyrene (84%), benzo(k)fluoranthene (57%) and benzo(e)pyrene (50%) at a 30 g/L NaCl concentration. The present study reveals that the VA1 strain was able to degrade PAHs in petroleum wastewater under saline conditions. The promising PAH-degrading halotolerant bacterial strain, VA1, was identified as Ochrobactrum sp. using biochemical and molecular techniques.

Role of a moderately halophilic bacterial consortium in the biodegradation of polyaromatic hydrocarbons.

Polycyclic aromatic hydrocarbons are ubiquitous pollutants in the environment, and most high molecular weight PAHs cause mutagenic, teratogenic and potentially carcinogenic effects. While several strains have been identified that degrade PAHs, the present study is focused on the degradation of PAHs in a marine environment by a moderately halophilic bacterial consortium. The bacterial consortium was isolated from a mixture of marine water samples collected from seven different sites in Chennai, India. The low molecular weight (LMW) PAHs phenanthrene and fluorine, and the high molecular weight (HMW) PAHs pyrene and benzo(e)pyrene were selected for the degradation study. The consortium metabolized both LMW and HMW PAHs. The consortium was also able to degrade PAHs present in crude oil-contaminated saline wastewater. The bacterial consortium was able to degrade 80% of HMW PAHs and 100% of LMW PAHs in the saline wastewater. The strains present in the consortium were identified as Ochrobactrum sp., Enterobacter cloacae and Stenotrophomonas maltophilia. This study reveals that these bacteria have the potential to degrade different PAHs in saline wastewater.

Role of plasmid in the degradation of petroleum hydrocarbon by Pseudomonas fluorescens NS1.

In this study the role of plasmid in Pseudomonas fluorescens, isolated from petroleum contaminated soil on hexadecane degradation was assessed. The organism was able to utilize hexadecane as sole carbon source and also reduce surface tension up to 27 mN/m. The organism harboured a plasmid of approximately 1.8 kb. Plasmid curing and transformation of plasmid DNA into E. coli revealed that the plasmid was involved in hexadecane degradation. When compared to P. fluorescens, no significant growth was observed with wild-type E. coli strain. P. fluorescens degraded 95% of hexadecane (0.4% (v/v)) whereas the transformed strain degraded 92% of hexadecane in 120 h, which was almost equivalent to the degradation by P. fluorescens. The wild-type E. coli showed no significant degradation of hexadecane whereas, the plasmid transformed E. coli was able to degrade hexadecane, which indicates the expression of the catabolic genes in the transformed E. coli strain.