Bt (Bacillus thuringiensis) is a soil bacterium renowned for its potent toxicity against various pests. Its primary application is as a biopesticide, offering agriculture an eco-friendly, sustainable, and effective method of pest control. The utilization of Bt as a natural pesticide has reduced the demand for chemical pesticides, presenting new possibilities for ecosystem and biodiversity conservation. Furthermore, Bt has been used in the development of genetically modified crops, such as Bt cotton and Bt corn, which can fend off pest invasions autonomously, thus enhancing yields.

In this biopesticide revolution, Ernst Berliner occupies a distinct position. Not only was he the discoverer of Bt, but he was also a pioneering researcher in the field. Through the in-depth studies on Bt, Berliner provided invaluable knowledge about this bacterium, laying a solid foundation for future scientists.

Although Bt was first identified in silkworms in 1901 by Japanese sericultural engineer Ishiwata Shigetane, it was the research of German microbiologist Ernst Berliner that truly brought fame to Bt. In 1911, while Berliner was investigating the flour moth larvae in the Thuringia region, he came across this bacterium, identifying it as the causative agent of the disease. By 1915, he named it B. thuringiensis, distinguishing it from the previously identified B. sotto, and detailed the bacterium’s effects on flour moth larvae. It was Berliner’s work that provided subsequent researchers with a valuable research foundation, opening the path to Bt’s widespread application in agriculture.

Bt is a Gram-positive, spore-forming bacillus, existing in the natural environment, especially in soil. A distinctive feature of this bacterium is its ability to produce a unique crystal protein, which possesses lethal toxicity to many insect larvae. This attribute makes Bt an ideal choice for pest control in agriculture, especially in organic and sustainable farming practices.

With the deepening understanding of the mechanisms behind Bt toxins and the advancement of biotechnology, the application of Bt in agriculture has been steadily expanding. It’s not just employed as a biopesticide sprayed onto fields but also in developing genetically modified crops resistant to insects. Compared to conventional chemical pesticides, Bt products are considered safer and more environmentally friendly.

1 Ernst Berliner: the Discoverer of Bacillus thuringiensis

Ernst Berliner, born on September 15, 1880, in Berlin and passed away on October 28, 1957, was a distinguished German scientist with significant contributions to microbiology, entomology, and biochemistry.

Berliner was raised in Berlin and completed his early education at the Humboldt Gymnasium. Subsequently, he studied engineering and natural sciences at the Royal Melbourne Institute of Technology and Humboldt-Universitat zu Berlin. In the early stages of his academic career, Berliner collaborated with eminent scholars such as Oscar Hertwig and Rudolf Virchow.

In 1909, Berliner commenced his work at the Cereal Processing Research Institute in Berlin. It was here that he studied an infectious disease affecting flour moth larvae and first named it Bacillus thuringiensis. These pivotal discoveries were published in 1911 and 1915, laying a solid foundation for subsequent research on bio-pesticides.

Beyond his academic accomplishments, Berliner’s life was marked by challenges. Following the outbreak of World War I, he volunteered for the frontlines and was awarded the Iron Cross for his valor. During the Nazi regime, he faced severe persecution due to racial and political reasons, including restrictions on his work, publication bans, and even a temporary detainment by the Gestapo alongside his wife.

Nevertheless, despite these adversities, Berliner remained steadfast in his academic pursuits, continually contributing to the field of cereal chemistry. The Cereal Chemistry Research Institute he founded offers an invaluable research platform for future scholars.

In 1955, Ernst Berliner was honored with a medal in recognition of his outstanding academic contributions. His life serves as a testament to both relentless scientific exploration and unwavering resilience in the face of adversity.

2 The Discovery Process of Bt

2.1 Background of Bt’s discovery

At the beginning of the 20th century, with the rapid development of industrialization and the growth of the population, agriculture also experienced swift progress. However, concurrently, insect pests emerged as a serious threat to agricultural production. Against this backdrop, scientists from various countries were actively seeking new methods to control these pests.

In the early 20th century, the silk industry in Japan was a significant sector, but pests and diseases were its primary hindrances. In 1901, a Japanese sericultural engineer named Ishiwata Shigetane first identified a disease in silkworms called “sotto”. This disease led to the extensive mortality of silkworms, having a substantial impact on the sericulture industry. Ishiwata’s discovery initiated research into the cause of this ailment, paving the way for the eventual discovery of Bt.

Over a decade later, German microbiologist Ernst Berliner identified a disease in flour moths resembling the “sotto” ailment, which he named “Schlaffsucht” (in German, meaning “sleeping sickness”). This disease rendered the infected flour moths incapacitated, eventually leading to their demise. Berliner realized this could be a new microbial pathogen and decided to delve deeper into its study.

2.2 Detailed description of Berliner’s initial isolation and identification of the bacterium

Berliner began detailed dissection and microscopic observations of the flour moths affected by “Schlaffsucht”. Within them, he discovered a profusion of bacteria. Through pure culturing of these bacteria, he successfully isolated the bacteria from the infected flour moths. Under microscopic examination, he found these bacteria to be rod-shaped and capable of producing spores and crystals that could inflict lethal damage on insects. Based on these observations and experimental results, Berliner concluded that this bacterium was the pathogen responsible for the “Schlaffsucht” disease.

To further confirm the characteristics of this bacterium, Berliner carried out meticulous biochemical analyses and tests, including toxicity tests. He found that the bacterium was toxic only to certain specific pests and was safe for humans and other flora and fauna.

2.3 Preliminary experiments and observations on Bt

To gain a deeper understanding of the bacterium’s characteristics and how it affects insects, Berliner conducted a series of experiments. He first observed the reactions of infected insects, noting that the infected insects, upon consuming the bacterium, would soon fall into a dormant state, cease feeding, and ultimately die.

Furthermore, he observed the bacterium’s ability to survive and reproduce within the insect. Through microscopic examination, Berliner found that the bacteria primarily proliferated in the insect’s gut and killed the insect by producing toxic crystals.

Berliner also tested the bacterium’s growth conditions, temperature, light exposure, and pH to understand its optimal conditions for survival and reproduction. These preliminary experiments laid a solid foundation for subsequent research and also unveiled the immense potential of Bt as a biopesticide.

3 The Story Behind the Naming of Bt

In 1901, Japanese sericultural engineer Ishiwata Shigetane first isolated this particular bacterium while studying diseased silkworms. Observing the physiological state of silkworms infected with this bacterium, Ishiwata named it B. sotto. In Japanese, the term “sotto” means “collapse” or “fainting”.

By 1915, the German microbiologist Ernst Berliner independently discovered the same bacterium in the Thuringia region. At that time, he was examining a disease affecting flour moth larvae called “Schlaffsucht”. Due to Berliner’s consideration of discovering this disease in the Thuringia region, he named this bacterium B. thuringiensis. This marked the official naming and scientific recognition of Bt. Subsequently, B. sotto was reclassified as B. thuringiensis var. sotto, linking Ishiwata’s discovery with Berliner’s research.

Naming a newly discovered bacterium is both an honor and a responsibility for a microbiologist. Berliner’s choice of the name “thuringiensis” for the bacterium, derived from Thuringia - the German state where it was first identified - is a tribute to the region’s contribution to the discovery of Bt.

The term “Bacillus” in Latin means “small stick”, indicating the rod-like shape of this class of bacteria, while “Thuringiensis” emphasizes its geographical origin. Together, Bacillus thuringiensis stands for a rod-shaped bacterium originating from Thuringia.

4 Berliner’s Legacy and Its Influence on Modern Bt Research

Bt (Bacillus thuringiensis) holds a significant position in the fields of microbiology, agriculture, biotechnology, and environmental protection, and this is largely attributed to the pioneering research of Ernst Berliner. Berliner’s studies not only laid a solid foundation for the application of Bt, but also provided invaluable research directions for subsequent scholars.

4.1 Berliner’s outstanding contribution to Bt Research and its influence on modern science

Berliner was the first to describe Bt and through experiments, he identified its specific toxicity to certain insects, laying the groundwork for the bacterium’s naming and classification. His research unveiled the basic principles of the interaction between Bt toxins and insect pests, offering a clear path for subsequent researchers. Building on his work, the scientific community began to explore how Bt toxins interact with the digestive systems of insect pests, leading to their demise.

In modern agriculture, Bt has emerged as an essential biopesticide. With the aid of contemporary molecular biology techniques, Bt genes have been introduced into various crops, rendering them resistant to pests and thereby reducing the use of chemical pesticides and the subsequent environmental contamination. These genetically modified crops not only help increase agricultural yield but also reduce the residues of chemical pesticides, making food safer. Many of these applications owe a great deal to Berliner’s initial discoveries and studies.

Additionally, research on Bt has had profound effects on the development of several disciplines, including microbial ecology, insect physiology, and genetics. Scholars, building on Bt's foundation, have delved into topics such as insect ecological behavior, resistance development, and the mechanisms of toxin action.

4.2 How Berliner’s contribution is commemorated and recognized in modern Bt research

Berliner’s research on Bt is widely recognized by scholars as one of the milestones in the field of microbiology. In many academic studies, Berliner’s foundational work is frequently cited as the starting point and reference for Bt research.

Numerous research institutions across different countries and regions have established awards or academic activities named after Berliner to encourage and motivate young scholars to conduct research in Bt and related fields. These awards and activities serve as recognition and commemoration of Berliner’s outstanding contribution to the Bt research arena.

Furthermore, many textbooks and monographs on Bt offer detailed accounts of Berliner’s research, enabling subsequent scholars and students to grasp his pivotal contributions to the field. This also reflects the academic community’s respect and acknowledgment of Berliner’s work.

In conclusion, Ernst Berliner’s groundbreaking efforts in the realm of Bt research have set the direction for future scholars and solidified the foundation for Bt’s application in agriculture and other fields. His contributions are widely acknowledged by scholars and are amply commemorated and recognized in contemporary Bt research.

5 Conclusion

From both a historical perspective and a modern viewpoint, Bt stands out as an invaluable resource. It’s not just a natural insect killer, it’s also a powerful biotechnological tool offering endless possibilities for human agricultural production and ecological preservation. Ernst Berliner is the pioneer behind all of this, and his contributions are undoubtedly immeasurable.

Looking back, the vast potential of Bt is clear to see. In contemporary society, the significance of Bt has become even more prominent. In the realm of agriculture, Bt has established itself as a representative of biopesticides, offering a green, efficient, and safe means of plant protection on a global scale. Distinct from chemical pesticides, Bt is characterized by its natural origin and absence of residues. It not only effectively combats pests but also minimizes potential harm to the environment and human health.

In the realm of biotechnology, the applications of Bt are diverse. Utilizing modern genetic engineering, we are now capable of introducing Bt genes into plants, creating genetically modified crops resistant to pests. These crops not only drastically reduce the need for pesticides but also enhance crop yield and quality, catering to the ever-growing global demand for food.

The utility of Bt isn’t restricted merely to agriculture and biotech. In the realm of environmental protection, Bt assumes a crucial role. Being a naturally occurring bacterium, its toxicity to pests doesn't harm other non-target organisms. Hence, in areas like biodiversity conservation and ecological restoration, Bt has found extensive application.

6 Timeline of Ernst Berliner

September 15, 1880: Ernst Berliner was born in Berlin, and his parents are Albrecht Berliner and Hedwig Koppen.

1901: Graduated from Humboldt Gymnasium.

1900~1904: Studied engineering at the Royal Melbourne Institute of Technology in Charlottenburg.

1904-1908: Studied natural sciences at Frederick William University (now Humboldt-Universitat zu Berlin).

May 8, 1909: Earned his Doctor of Philosophy with a research focus on flagellates and published a paper titled “Research on Flagellates”.

1909~1912: Worked at the Cereal Processing Research Institute in Berlin and studied an infectious disease in flour moth larvae named Bacillus thuringiensis.

1911: Reported his findings on Bacillus thuringiensis in the “Die Kulturpflanze” for the first time.

1915: Published a detailed study about Bacillus thuringiensis in the “Zeitschrift für angewandte Entomologie”.

1912~1914: Served as the head of the Agrochemical Control Station of the Agricultural Bureau in Halle, Saxony-Anhalt.

1914~1919, World War I: Volunteered for service during the World War I, serving as a lieutenant and company commander in France and Russia, and was awarded the Second and First Iron Cross medals.

1920: Became the chief chemist at the Swedish milling company Malmö Stora Walskvarn.

1921: Married Helene Martha Ast (passed away in 1954). They had two children: Kurt Albrecht (1921~1944) and Hildur Hedwig (born in 1928).

1927: Became the Director of the Research Institute for Cereal Chemistry in MIAG (Maschinenfabrik und Eisengießerei Actiengesellschaft) in Frankfurt.

1931: Founded the independent Research Institute for Cereal Chemistry in Darmstadt-Eberstadt.

1927~1933: Served as the Associate Professor of Cereal Chemistry at the Technische Universität Darmstadt.

1936~1938: Conducted scientific training courses in Vienna, Prague, Zurich, and Paris.

1944, Nazi era: Faced racial and political persecution. He and his wife were temporarily detained by the Gestapo.

1949: Resumed operations at his Research Institute for Cereal Chemistry in Darmstadt-Eberstadt with the assistance of chemist Dr. Kurt Neitzert (born November 22, 1910, in Oberlahnstein).

1950: Initiated the annual “Jülichheim Conference” for the Cereal Chemistry Working Group.

1955: Was awarded the Cross Medal.

October 28, 1957: Passed away in Albach/Bergstraße at the age of 77, and he was buried in the cemetery of Darmstadt-Eberstadt.

References

Berliner E., Krieg A., and Huger A. M., 1986, Symposium in memorium Dr. Ernst Berliner on the occasion of the 75th anniversary of the first description of Bacillus thuringiensis.

Berliner E., 1915, Ueber die schlaffsucht der Ephestia kuhniella und Bac. thuringiensis n. sp. Z Angew Entomol, 2, 21-56.

Ishiwata S., 1905b, About “Sottokin”, a bacillus of a disease of the silk-worm, Dainihon Sanshi Kaiho (Rept Assoc Seric Japan), 161:1-5.

Ishiwata S., 1901, On a new type of severe flacherie (sotto disease) (original in Japanese), Dainhon Sansi Kaiho 114:1-5.

Reardon R.C., Dubois N.R., McLane W., 1994, Bacillus thuringiensis for managing gypsy moth: a review, Mediterranean flour moths, Ephestia (=Anagasta) kuehniella (Zeller), that were found in stored grain in Thuringia.

https://doi.org/10.5962/bhl.title.141061

Steinhaus E., 2012, Insect Pathology V1: An Advanced Treatise, Elsevier, p. 32, ISBN 978-0-323-14317-2, Bacillus sotto Ishiwata Taxonomic reassignment: Bacillus thuringiensis var. sotto Ishiwata. [Heimpel and Angus, 1960]