https://stm2.bookpi.org/MBBHO/issue/feed 2025-09-08T05:36:13+00:00 Open Journal Systems <p>The modern world relies heavily on mineral oils. These substances are not only used as fuels for transportation and industry but also serve as essential components in manufacturing and machinery. However, this widespread dependence has led to serious environmental problems. In Japan, extensive use and improper management of mineral oils have resulted in significant soil and groundwater contamination, raising public health concerns and requiring large-scale remediation.</p> <p>Among the various petroleum pollutants, heavy crude oils are particularly problematic. Their complex structure makes them less volatile and more persistent in the environment. They tend to adhere strongly to soil particles and degrade slowly, especially under cold conditions. This makes cleanup efforts both technically difficult and costly.</p> <p>Bioremediation offers a promising path forward. By using the natural metabolic processes of microorganisms, it is possible to break down and detoxify harmful oil components in a way that is cost-effective and environmentally sound. Research in recent years has shown the potential of cold-tolerant bacteria to play a key role in this process, even in challenging climates like Hokkaido.</p> <p>This book presents a scientific exploration of such microbial solutions. It examines the characteristics of heavy oil pollutants, the limitations of existing remediation techniques, and the promise of microbial consortia adapted to cold environments. The chapters that follow are grounded in fieldwork, laboratory findings, and a review of regulatory and ecological contexts relevant to Japan and beyond.</p> <p>This work aims to contribute to the development of sustainable and practical remediation strategies. It is intended for researchers, environmental engineers, policy makers, and all those interested in cleaner technologies and ecological recovery. Through deeper understanding and collaboration, we can move closer to restoring polluted environments and building a more sustainable future.</p> https://stm2.bookpi.org/MBBHO/article/view/360 2025-09-08T05:36:13+00:00 YOUNG-CHEOL CHANG [email protected]

<p>Heavy oil, characterised by its complex hydrocarbon composition and inherent resistance to biodegradation, represents a persistent environmental contaminant. Despite extensive industrial usage, the understanding of its biodegradability under varying environmental conditions remains limited. This study systematically investigates the biodegradation potential of heavy oil by indigenous microbial consortia derived from soil and water samples, under both aerobic and anaerobic conditions. Using gas chromatography to quantify residual hydrocarbons, it was demonstrated that aerobic soil-derived microbial communities achieve superior degradation efficiencies, with removal rates reaching up to 80.3%, significantly outperforming water-derived consortia, which attained a maximum of 52.1%. In contrast, anaerobic conditions markedly inhibit biodegradation, with maximum removal efficiencies of 43.7% and 11.1% for water- and soil-derived microbes, respectively. Correlative analyses reveal a positive association between initial microbial biomass—particularly heterotrophic and hydrocarbon-degrading bacteria—and degradation performance. The persistence of polycyclic aromatic hydrocarbons under anaerobic conditions underscores the recalcitrance of certain heavy oil fractions. These findings elucidate the pivotal roles of microbial community composition and oxygen availability in governing biodegradation dynamics, providing critical insights for optimising bioremediation strategies. Nonetheless, technological challenges persist, including incomplete mineralisation of heavy oil residues and suboptimal oxygen transfer in heterogeneous, large-scale sites. Addressing these issues will require the refinement of microbial consortia, the advancement of innovative biostimulation techniques, and the integration of complementary remediation technologies. Such developments hold substantial promise for delivering sustainable, cost-effective solutions to mitigate heavy oil pollution across diverse industrial and natural environments.</p>

2025-09-08T00:00:00+00:00 Copyright (c) 2025 Author(s). The licensee is the publisher (BP International).