【大学受験対策】英語長文問題70（発酵）399語＋和訳・解答解説

Fermentation, a process discovered thousands of years ago, was initially regarded as a mysterious transformation that turned raw ingredients into foods with extended shelf lives and distinctive flavors. Ancient societies fermented grains into beer, grapes into wine, and milk into cheese or yogurt, long before they had any knowledge of microbiology. For centuries, people attributed these transformations to spontaneous processes or even divine intervention. It was not until the nineteenth century, with the pioneering work of Louis Pasteur, that the crucial role of microorganisms was scientifically recognized. Pasteur demonstrated that yeast and bacteria were not contaminants but active agents responsible for producing alcohol, acids, and gases during fermentation.

From a biochemical perspective, fermentation is a metabolic strategy that allows microbes to generate energy in the absence of oxygen. Yeast cells, for example, convert glucose into ethanol and carbon dioxide through a series of enzymatic reactions. Lactic acid bacteria, by contrast, metabolize sugars into lactic acid, creating the tangy flavor in yogurt and sauerkraut. Although fermentation is less efficient than aerobic respiration in terms of energy yield, it provides an evolutionary advantage in environments where oxygen is scarce. In addition, the by-products of microbial metabolism often inhibit competing organisms, giving fermenting microbes a defensive edge.

Modern science has expanded our understanding of fermentation beyond its nutritional and preservative benefits. Today, fermentation is a cornerstone of biotechnology and pharmaceutical production. Microorganisms are carefully engineered to synthesize antibiotics, vitamins, and even biofuels. Genetic modification enables scientists to optimize metabolic pathways, allowing microbes to produce substances they would not naturally create. This harnessing of microbial power demonstrates the profound shift from observing fermentation as a natural curiosity to applying it as a controlled industrial tool. Such applications not only meet human needs but also highlight the versatility and adaptability of microbial life.

Yet, the significance of fermentation extends beyond science and industry. Fermented foods represent cultural heritage, linking generations through shared practices of taste and tradition. Kimchi in Korea, miso in Japan, and sourdough bread in Europe all embody the intersection of microbial activity and human creativity. As research continues, scientists are also uncovering links between fermented foods and gut health, suggesting that the microbes we consume may influence digestion, immunity, and even mental well-being. Thus, the study of fermentation reminds us that our relationship with microbes is not merely technical but deeply intertwined with culture, health, and the future of sustainable living.

Q1. What most accurately describes Pasteur’s contribution to understanding fermentation?

1. He proved microbes actively drive fermentation, not accidental contamination.
2. He showed ancient brewers relied on divinely sanctioned natural forces.
3. He invented yogurt by isolating lactic acid bacteria strains.
4. He concluded oxygen is essential for all energy-producing processes.

Q2. Which statement best captures contemporary applications of microbial fermentation?

1. Industrial fermentation replaced all traditional food practices across cultures.
2. It mainly preserves foods by limiting growth of spoilage organisms.
3. Scientists avoid genetic modification, favoring strictly natural fermentation pathways.
4. Engineered microbes produce medicines and fuels via optimized metabolic pathways.

Q3. Which statement is NOT supported by the passage?

1. Fermented foods can influence digestion, immunity, and potentially mental well-being.
2. Fermentation typically yields more energy than oxygen-based cellular respiration.
3. Microbial processes are deliberately controlled as versatile industrial production tools.
4. Fermenting microbes gain advantage by producing inhibitory metabolic by-products.