Potential applications of bioprocess technology in petroleum industry

New aspects of lipopeptide-incorporated nanoparticle synthesis and recent advancements in biomedical and environmental sciences: a review

The toxicity of metal nanoparticles has introduced promising research in the current scenario since an enormous number of people have been potentially facing this problem in the world. The extensive attention on green nanoparticle synthesis has been focussed on as a vital step in bio-nanotechnology to improve biocompatibility, biodegradability, eco-friendliness, and huge potential utilization in various environmental and clinical assessments. Inherent influence on the study of green nanoparticles plays a key role to synthesize the controlled and surface-influenced molecule by altering the physical, chemical, and biological assets with the provision of various precursors, templating/co-templating agents, and supporting solvents. However, in this article, the dominant characteristics of several kinds of lipopeptide biosurfactants are discussed to execute a critical study of factors affecting synthesis procedure and applications. The recent approaches of metal, metal oxide, and composite nanomaterial synthesis have been deliberated as well as the elucidation of the reaction mechanism. Furthermore, this approach shows remarkable boosts in the production of nanoparticles with the very less employed harsh and hazardous processes as compared to chemical or physical method-based nanoparticle synthesis. This study also shows that the advances in strain selection for green nanoparticle production could be a worthwhile and strong economical approach in futuristic medical science research.

Enhanced Oil Recovery by Potential Biosurfactant-Producing Halo-thermotolerant Bacteria Using Soil Washing and Sand-Packed Glass Column Techniques

Biosurfactants offer numerous advantages over the chemical surfactants, especially in energy and environment-related applications. Microbial enhanced oil recovery (MEOR) is a technique to recover oil from reservoirs by using microbes and their metabolites. In present study, total sixteen morphologically distinct bacterial strains isolated from different salty areas of the district Khairpur Mir's, Pakistan, were investigated for their MEOR potential. Screening assays for thermotolerance and halotolerance declared 7 out of 16 (43.75%) bacterial isolates as thermotolerant (capable of growing in the temperature range 60-70 °C) and halotolerant (tolerating NaCl concentrations up to 17%, w/v). Moreover, five of them were screened as biosurfactant producers. Among, the lowest surface tension reduction was achieved with biosurfactants produced by the strains KJ2MO (27.8 mN/m) and KJ2SK (29.3 mN/m). The biosurfactant activity was found stable at temperature (100-121 °C, 1 h) and pH (4-10). Moreover, maximum oil recovery was obtained with biosurfactant of bacterial strain KJ2MO (54.7%, 51.25%) followed by KJ2SK (44.7%, 40.5%), KJ1WB (37%, 35.5%) and KJ2MD (37.8%, 31.9%) by using either techniques, i.e., soil washing and sand-packed column, respectively. Moreover, the potent species were identified as Pseudomonas pseudoalcaligenes KJ1WB, Bacillus aerius KJ2MD, Bacillus licheniformis KJ2SK, and Bacillus subtilis KJ2MO using 16S rRNA ribo-typing. The investigated species were found to be promising biosurfactants producers having potential for enhanced oil recovery and could be used in other environmental applications like bioremediation.

Effects of hydropower dam construction on sulfur distribution and sulfate-reducing prokaryotes assemblage

River damming is significant for hydropower production, but also alters the ecological conditions, and especially affects the microbial community. Sulfate-reducing prokaryotes (SRPs) make vital contributions to biogeochemical sulfur cycle, but the information on the effects of dam construction on the SRPs assemblage are unclear. Here, a comprehensive survey was conducted by collecting water and sediment samples along horizontal and vertical profiles from six sites at the Xiaowan Reservoir on the Lancang River, China. We used 16S rRNA gene amplicon sequencing and qPCR assay with dsrB gene to study the composition and activity of SRPs. The results indicated that river damming accumulated nutrients in the middle layer of the reservoir, and the impoundment provided an anaerobic and high nutrient available environment, which is beneficial for the survival of SRPs. The abundance and diversity of SRPs in water and sediments at the bottom of the reservoir were higher than those in the other sites. The network analyses revealed a synergistic effect between SRPs and other dominant bacteria in water column, which was more complex than in sediments. Moreover, a relatively higher sulfate reduction activity was found in the middle and lower layers of the water profile according to dsrB gene analysis.

Changes in the Microbial Community Diversity of Oil Exploitation

To systematically evaluate the ecological changes of an active offshore petroleum production system, the variation of microbial communities at several sites (virgin field, wellhead, storage tank) of an oil production facility in east China was investigated by sequencing the V3 to V4 regions of 16S ribosomal ribonucleic acid (rRNA) of microorganisms. In general, a decrease of microbial community richness and diversity in petroleum mining was observed, as measured by operational taxonomic unit (OTU) numbers, α (Chao1 and Shannon indices), and β (principal coordinate analysis) diversity. Microbial community structure was strongly affected by environmental factors at the phylum and genus levels. At the phylum level, virgin field and wellhead were dominated by Proteobacteria, while the storage tank had higher presence of Firmicutes (29.3-66.9%). Specifically, the wellhead displayed a lower presentence of Proteobacteria (48.6-53.4.0%) and a higher presence of Firmicutes (24.4-29.6%) than the virgin field. At the genus level, the predominant genera were Ochrobactrum and Acinetobacter in the virgin field, Lactococcus and Pseudomonas in the wellhead, and Prauseria and Bacillus in the storage tank. Our study revealed that the microbial community structure was strongly affected by the surrounding environmental factors, such as temperature, oxygen content, salinity, and pH, which could be altered because of the oil production. It was observed that the various microbiomes produced surfactants, transforming the biohazard and degrading hydro-carbon. Altering the microbiome growth condition by appropriate human intervention and taking advantage of natural microbial resources can further enhance oil recovery technology.

Biodesulfurization of Petroleum Distillates—Current Status, Opportunities and Future Challenges

Sulfur oxide (SO2) and hydrogen sulfide (H2S) are considered as one of the major air pollutants in the world today. In addition, high sulfur levels in petroleum distillates can promote the deactivation of catalysts through poisoning in fluidized catalytic cracking (FCC) during hydrocracking of the heavy distillates to lighter ones. The presence of high sulfur-containing compounds in the process streams could cause corrosion of piping and fittings and equipment, thereby damaging the pipelines and leading to air emissions of sulfur-containing compounds, which are undesirable for mankind and his environment. In many cases, a large quantity of SOx is released into the atmosphere when petroleum distillates that contain substantial amount of sulphur-containing compounds are used as fuel and combust. In this article, a short overview of different desulfurization methods that are employed to remove sulfur from petroleum distillates is provided. In particular, the review concentrates on biodesulfurization technique. In addition, this article intends to provide its readers current status of biodesulfurization (BDS). It critically analyses the trend in the development of the technology to showcase its strength and weakness that could pave a way for future opportunities. Approaches that are suitable to remediate sulfur-contaminated environment are discussed as well. Lastly, speculations on future directions or opportunities that require exploration are provided as a way of provoking the thoughts of researchers in this field.

Bioremediation of Heavy Crude Oil Contamination

Crude oil contamination is one of the major environmental concerns and it has drawn interest from researchers and industries. Heavy oils contain 24-64% saturates and aromatics, 14-39% resins and 11-45% asphaltene. Resins and asphaltenes mainly consist of naphthenic aromatic hydrocarbons with alicyclic chains which are the hardest to degrade. Crude oil biodegradation process, with its minimal energy need and environmentally friendly approach, presents an opportunity for bioremediation and as well for enhanced oil recovery to utilize heavy oil resources in an efficient manner. Biodegradation entails crude oil utilization as a carbon source for microorganisms that in turn change the physical properties of heavy crude oil by oxidizing aromatic rings, chelating metals and severing internal bonds/chains between molecules. Biodegradation does not necessarily lower quality of crude oil as there are cases where quality was improved. This paper provides information on heavy crude oil chemistry, bioremediation concept, biodegradation enzymes, cases of Microbial Enhanced heavy crude Oil Recovery (MEOR) and screening criteria towards a better understanding of the biodegradation application. Through the utilization of single microorganisms and consortia, researchers were able to biodegrade single pure hydrocarbon components, transform heavy crude oil fractions to lighter fractions, remove heavy metals and reduce viscosity of crude oil.

Biosurfactants: Promising Molecules for Petroleum Biotechnology Advances

The growing global demand for sustainable technologies that improves the efficiency of petrochemical processes in the oil industry has driven advances in petroleum biotechnology in recent years. Petroleum industry uses substantial amounts of petrochemical-based synthetic surfactants in its activities as mobilizing agents to increase the availability or recovery of hydrocarbons as well as many other applications related to extraction, treatment, cleaning, and transportation. However, biosurfactants have several potential applications for use across the oil processing chain and in the formulations of petrochemical products such as emulsifying/demulsifying agents, anticorrosive, biocides for sulfate-reducing bacteria, fuel formulation, extraction of bitumen from tar sands, and many other innovative applications. Due to their versatility and proven efficiency, biosurfactants are often presented as valuable versatile tools that can transform and modernize petroleum biotechnology in an attempt to provide a true picture of state of the art and directions or use in the oil industry. We believe that biosurfactants are going to have a significant role in many future applications in the oil industries and in this review therefore, we highlight recent important relevant applications, patents disclosures and potential future applications for biosurfactants in petroleum and related industries.

Advances in the Reduction of the Costs Inherent to Fossil Fuels' Biodesulfurization towards Its Potential Industrial Application

Biodesulfurization (BDS) process consists on the use of microorganisms for the removal of sulfur from fossil fuels. Through BDS it is possible to treat most of the organosulfur compounds recalcitrant to the conventional hydrodesulfurization (HDS), the petroleum industry's solution, at mild operating conditions, without the need for molecular hydrogen or metal catalysts. This technique results in lower emissions, smaller residue production and less energy consumption, which makes BDS an eco-friendly process that can complement HDS making it more efficient. BDS has been extensively studied and much is already known about the process. Clearly, BDS presents advantages as a complementary technique to HDS; however its commercial use has been delayed by several limitations both upstream and downstream the process. This study will comprehensively review and discuss key issues, like reduction of the BDS costs, advances and/or challenges for a competitive BDS towards its potential industrial application aiming ultra low sulfur fuels.

Jerusalem artichoke as low-cost fructose-rich feedstock for fossil fuels desulphurization by a fructophilic bacterium

AIMS

Through biodesulphurization (BDS) is possible to remove the sulphur present in fossil fuels to carry out the very strict legislation. However, this biological process is limited by the cost of the culture medium, and thus, it is important to explore cheaper alternative carbon sources, such as Jerusalem artichoke (JA). These carbon sources usually contain sulphates which interfere with the BDS process. The goal of this work was to remove the sulphates from Jerusalem artichoke juice (JAJ) through BaCl2 precipitation viewing the optimization of dibenzothiophene (DBT) desulphurization by Gordonia alkanivorans strain 1B.

METHODS AND RESULTS

Using a statistical design (Doehlert distribution), the effect of BaCl2 concentration (0.125-0.625%) and pH (5-9) was studied on sulphate concentration in hydrolysed JAJ. A validated surface response derived from data indicated that zero sulphates can be achieved with 0.5-0.55% (w/v) BaCl2 at pH 7; however, parallel BDS assays showed that the highest desulphurization was obtained with the juice treated with 0.5% (w/v) BaCl2 at pH 8.73. Further assays demonstrated that enhanced DBT desulphurization was achieved using hydrolysed JAJ treated in these optimal conditions. A total conversion of 400 μmol l(-1) DBT into 2-hydroxybiphenyl (2-HBP) in <90 h was observed, attaining a 2-HBP maximum production rate of 28.2 μmol l(-1) h(-1) and a specific production rate of 5.06 μmol(-1) g(-1) (DCW) h(-1) .

CONCLUSIONS

These results highlight the efficacy of the treatment applied to JAJ in making this agromaterial a promising low-cost renewable feedstock for improved BDS by the fructophilic strain 1B.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is a fundamental step viewing BDS application at the industrial level as it accounts a cost-effective production of the biocatalysts, one of the main drawbacks for BDS scale-up.