Reia Hosokawa

Bio: Reia Hosokawa is an academic researcher from Hokkaido University. The author has contributed to research in topics: Microbial consortium & Bioaugmentation. The author has an hindex of 3, co-authored 4 publications receiving 134 citations.

Autochthonous bioaugmentation and its possible application to oil spills

Abstract: Bioaugmentation for oil spills is a much more promising technique than is biostimulation. However, the effectiveness of bioaugmentation is variable, because the survival and the xenobiotic-degrading ability of introduced microorganisms are highly dependent on environmental conditions. As an alternative, autochthonous bioaugmentation (ABA) is proposed to overcome these difficulties. The ABA method is like a ready-made bioaugmentation technology. In ABA, microorganisms indigenous to the contaminated site or predicted contamination site that are well-characterized and potentially capable of degrading oils are used, and these microorganisms should be enriched under conditions where bioaugmentation will be conducted. It is possible to obtain information in advance on the chemical and physical characteristics of potential oil spill sites and of oils that might be spilled. The application of ABA in the coastal areas of Hokkaido Prefecture, Japan, is considered here, because Hokkaido is located south of Sakhalin Island, Russia, where development of oil fields is in progress. If oil spills in this region were well characterized in advance, ABA could be a feasible technology in the near future.

Pesticide relevance and their microbial degradation: a-state-of-art

Abstract: The extensive use of pesticide causes imbalance in properties of soil, water and air environments due to having problem of natural degradation. Such chemicals create diverse environmental problem via biomagnifications. Currently, microbial degradation is one of the important techniques for amputation and degradation of pesticide from agricultural soils. Some studies have reported that the genetically modified microorganism has ability to degrade specific pesticide but problem is that they cannot introduce in the field because they cause some other environmental problems. Only combined microbial consortia of indigenous and naturally occurring microbes isolated from particular contaminated environment have ability to degrade pesticides at faster rate. The bioaugumentation processes like addition of necessary nutrients or organic matter are required to speed up the rate of degradation of a contaminant by the indigenous microbes. The use of indigenous microbial strains having plant growth activities is ecologically superior over the chemical methods. In this review, we have attempted to discuss the recent challenge of pesticide problem in soil environment and their biodegradation with the help of effective indigenous pesticides degrading microorganisms. Further, we highlighted and explored the molecular mechanism for the pesticide degradation in soil with effective indigenous microbial consortium. This review suggests that the use of pesticide degrading microbial consortia which is an eco-friendly technology may be suitable for the sustainable agriculture production.

The Interaction between Plants and Bacteria in the Remediation of Petroleum Hydrocarbons: An Environmental Perspective

Abstract: Widespread pollution of terrestrial ecosystems with petroleum hydrocarbons (PHCs) has generated a need for remediation and, given that many PHCs are biodegradable, bio- and phyto-remediation are often viable approaches for active and passive remediation. This review focuses on phytoremediation with particular interest on the interactions between and use of plant-associated bacteria to restore PHC polluted sites. Plant-associated bacteria include endophytic, phyllospheric, and rhizospheric bacteria, and cooperation between these bacteria and their host plants allows for greater plant survivability and treatment outcomes in contaminated sites. Bacterially driven PHC bioremediation is attributed to the presence of diverse suites of metabolic genes for aliphatic and aromatic hydrocarbons, along with a broader suite of physiological properties including biosurfactant production, biofilm formation, chemotaxis to hydrocarbons, and flexibility in cell-surface hydrophobicity. In soils impacted by PHC contamination, microbial bioremediation generally relies on the addition of high-energy electron acceptors (e.g., oxygen) and fertilization to supply limiting nutrients (e.g., nitrogen, phosphorous, potassium) in the face of excess PHC carbon. As an alternative, the addition of plants can greatly improve bioremediation rates and outcomes as plants provide microbial habitats, improve soil porosity (thereby increasing mass transfer of substrates and electron acceptors), and exchange limiting nutrients with their microbial counterparts. In return, plant-associated microorganisms improve plant growth by reducing soil toxicity through contaminant removal, producing plant growth promoting metabolites, liberating sequestered plant nutrients from soil, fixing nitrogen, and more generally establishing the foundations of soil nutrient cycling. In a practical and applied sense, the collective action of plants and their associated microorganisms is advantageous for remediation of PHC contaminated soil in terms of overall cost and success rates for in situ implementation in a diversity of environments. Mechanistically, there remain biological unknowns that present challenges for applying bio- and phyto-remediation technologies without having a deep prior understanding of individual target sites. In this review, evidence from traditional and modern omics technologies is discussed to provide a framework for plant-microbe interactions during PHC remediation. The potential for integrating multiple molecular and computational techniques to evaluate linkages between microbial communities, plant communities and ecosystem processes is explored with an eye on improving phytoremediation of PHC contaminated sites.

Biodegradation of petroleum sludge and petroleum polluted soil by a bacterial consortium: a laboratory study.

Abstract: This article presents a study of the efficiency and degradation pattern of samples of petroleum sludge and polluted sandy soil from an oil refinery. A bacterial consortium, consisting of strains from the genera Pseudomonas, Achromobacter, Bacillus and Micromonospora, was isolated from a petroleum sludge sample and characterized. The addition of nitrogen and phosphorus nutrients and a chemical surfactant to both the samples and bioaugmentation to the soil sample were applied under laboratory conditions. The extent of biodegradation was monitored by the gravimetric method and analysis of the residual oil by gas chromatography. Over a 12-week experiment, the achieved degree of TPH (total petroleum hydrocarbon) degradation amounted to 82–88% in the petroleum sludge and 86–91% in the polluted soil. Gas chromatography–mass spectrometry was utilized to determine the biodegradability and degradation rates of n-alkanes, isoprenoids, steranes, diasteranes and terpanes. Complete degradation of the n-alkanes and isoprenoids fractions occurred in both the samples. In addition, the intensities of the peaks corresponding to tricyclic terpenes and homohopanes were decreased, while significant changes were also observed in the distribution of diasteranes and steranes.