Isolation of four hydrocarbon effluent-degrading Bacillaceae species and evaluation of their ability to grow under high-temperature or high-salinity conditions

Four bacterial strains belonging to the family Bacillaceae were isolated from a polluted site and tested for their efficiency in degrading a refinery effluent highly polluted with hydrocarbons. Among 13 strains isolated, four were selected for their efficiency. Each of these four strains demonstrated a strong ability to grow as a single strain on a hydrocarbon effluent (HCE) as sole carbon source. In batch assays using clarified wastewater as diluent, the strains achieved high-percentage decreases in total hydrocarbon concentration within 18 days: 98% with Bacillus licheniformis STK08, 87% with Geobacillus stearothermophilus STM04, 80% with Lysinibacillus sphaericus STZ75 and 72% with Bacillus firmus STS84. The decreases were greater during the first three days of treatment, with 73, 66, 39 and 47% recorded for Bacillus licheniformis STK08, G. stearothermophilus STM04, L. sphaericus STZ75 and B. firmus STS84, respectively. Growth assays run under different conditions showed that B. licheniformis STK08 and G. stearothermophilus STM04 were able to grow at salinities of up to 120 g/L and at 55°C. Potential biosurfactant production tested using two methods namely modified drop collapse (MDC) and blue agar plate (BAP) demonstrated that the four Bacillaceae species are biosurfactant producers.Keywords: Hydrocarbons, biodegradation, pure culture, high salinity, high temperatureAfrican Journal of Biotechnology Vol. 12(14), pp. 1636-164

Bacillales: From Taxonomy to Biotechnological and Industrial Perspectives

first_page settings Order Article Reprints Open AccessReview Bacillales: From Taxonomy to Biotechnological and Industrial Perspectives by Sharareh Harirchi 1 [ORCID] , Taner Sar 1 [ORCID] , Mohaddaseh Ramezani 2, Habibu Aliyu 3 [ORCID] , Zahra Etemadifar 4 [ORCID] , Seyed Ali Nojoumi 5,6 [ORCID] , Fatemeh Yazdian 7, Mukesh Kumar Awasthi 8 [ORCID] and Mohammad J. Taherzadeh 1,* [ORCID] 1 Swedish Centre for Resource Recovery, University of Borås, 50190 Borås, Sweden 2 Microorganisms Bank, Iranian Biological Resource Centre (IBRC), Academic Center for Education, Culture and Research (ACECR), Tehran, Iran 3 Institute of Process Engineering in Life Science II: Technical Biology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany 4 Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan 8174673441, Iran 5 Microbiology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran 6 Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran 1316943551, Iran 7 Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran 1439957131, Iran 8 College of Natural Resources and Environment, Northwest A&F University, Taicheng Road 3#, Yangling, Xianyang 712100, China * Author to whom correspondence should be addressed. Microorganisms 2022, 10(12), 2355; https://doi.org/10.3390/microorganisms10122355 Received: 26 October 2022 / Revised: 18 November 2022 / Accepted: 21 November 2022 / Published: 28 November 2022 (This article belongs to the Section Microbial Biotechnology) Download Browse Figure Versions Notes Abstract For a long time, the genus Bacillus has been known and considered among the most applicable genera in several fields. Recent taxonomical developments resulted in the identification of more species in Bacillus-related genera, particularly in the order Bacillales (earlier heterotypic synonym: Caryophanales), with potential application for biotechnological and industrial purposes such as biofuels, bioactive agents, biopolymers, and enzymes. Therefore, a thorough understanding of the taxonomy, growth requirements and physiology, genomics, and metabolic pathways in the highly diverse bacterial order, Bacillales, will facilitate a more robust designing and sustainable production of strain lines relevant to a circular economy. This paper is focused principally on less-known genera and their potential in the order Bacillales for promising applications in the industry and addresses the taxonomical complexities of this order. Moreover, it emphasizes the biotechnological usage of some engineered strains of the order Bacillales. The elucidation of novel taxa, their metabolic pathways, and growth conditions would make it possible to drive industrial processes toward an upgraded functionality based on the microbial nature

Biodegradation of synthetic and biodegradable plastics by leachate microbiomes

Dissertação de mestrado em BiotecnologiaNos últimos anos, várias estratégias têm sido desenvolvidas para colmatar a acumulação de plásticos no ambiente, como a descoberta de novos microrganismos e enzimas que consigam eficientemente biodegradar plásticos. Neste trabalho, as comunidades microbianas de lixiviado, em aerobiose e anaerobiose em condições termófilas, foram estudadas pela sua capacidade de biodegradar polímeros não-biodegradáveis (PE (polietileno) e PET (politereftalato de etileno)) e biodegradáveis (PCL (policaprolactona e PHB/PBAT (polihidroxibutirato/poli (butileno adipato-co-tereftalato)). Esta biodegradação também foi testada utilizando sedimento marinho como inóculo, em condições aeróbicas, metanogénicas e sulfato-redutores em temperaturas mesófilas. As experiências com lixiviado demonstraram uma biodegradação completa com PCL em pó, em condições anaeróbicas e aeróbicas (103 ± 18 % e 99 ± 6 %, respetivamente), observando-se, também, uma biodegradação completa para o PCL em filme em condições anaeróbias (100 ± 0,2%), e uma biodegradação de 28 a 100% em condições aeróbias. PHB/PBAT demonstrou uma biodegradação parcial (24 % ± 0,2 %) em anaerobiose. Contudo, não se observou uma produção de metano/consumo de oxigénio significativa para o PE e PET, resultando numa baixa biodegradação. Mesmo assim, um dos ensaios demonstrou uma biodegradação aparente de 5 ± 2%, ao fim de 180 dias. As comunidades microbianas dos ensaios com PCL demonstraram ser distintas e diversas. Coprothermobacter estava presente em grande abundância nos ensaios aeróbios e anaeróbios e poderá ter estado diretamente ligado à biodegradação de PCL. Methanothermobacter demonstrou ser o microrganismo metanogénico mais abundante (mais de 55 % abundância relativa), tendo um papel importante na conversão do PCL a metano. Nos estudos com sedimento marinho, o PCL demonstrou ser biodegradado em condições aeróbias e sulfato-redutoras, mas não em condições metanogénicas. Até ao momento, a comunidade microbiana de sedimento não demonstrou ter capacidade para biodegradar PE e PET Estes resultados demostram que lixiviado e sedimento marinho são potenciais fontes de microrganismos com a capacidade de biodegradar PCL, sendo necessário mais estudos para isolar e caracterizar estas comunidades microbianas.In the last decades, various strategies have been developed to overcome the plastic waste problem, such as using biodegradable polymers, applying treatments that facilitate plastic degradation, and discovering novel microorganisms and enzymes that are capable of biodegrading complex polymers. This work explored leachate microbial communities in aerobic and anaerobic thermophilic conditions for their ability to biodegrade non-biodegradable (PE (polyethylene) and PET (polyethylene terephthalate)) and biodegradable (PCL (polycaprolactone) and PHB/PBAT (polyhydroxy butyrate/polybutylene adipate co-terephthalate blend)) polymers. Biodegradation was also tested with microbiomes from marine sediment, under aerobic, methanogenic, and sulphate-reducing mesophilic conditions. With leachate, complete biodegradation of powder PCL was observed both under anaerobic and aerobic conditions (103 ± 18 % and 99 ± 6 %, respectively). PCL films were fully converted to methane (100 ± 0,2%) under anaerobic conditions, and biodegradation under aerobic conditions ranged from 28 to 100 %. The blend PHB/PBAT was partially biodegraded under anaerobic conditions (24 ± 0,2 %). Generally, no significant methane production or oxygen consumption were detected in the assays with PE and PET, indicating no considerable biodegradation. Nevertheless, in one assay PE was apparently converted to methane (5 ± 2 % in 180 days), but further analyses are necessary to confirm this biodegradation. PCL-degrading microbial communities developed under aerobic and anaerobic assays were diverse and distinct. Coprothermobacter sp. was very abundant in aerobic and anaerobic incubations and was potentially involved in PCL biodegradation in both conditions. Methanothermobacter sp. was the most abundant methanogen (over 55 % relative abundance), being an important player during PCL conversion to methane. PCL was also biodegraded by the marine sediment, under aerobic and sulphate-reducing conditions, but not under methanogenic conditions. Thus far, the marine sediment microbiome did not biodegrade PE and PET. These results show that leachate and marine sediment microbiomes are potentially good sources of microorganisms with the ability to biodegrade PCL, and further attempts should be made to isolate key microorganisms, obtain efficient microbial consortia, facilitate microbial access to the polymers, and stimulate the activity of plastic-degrading microorganisms

Pseudomonads and bacilli as important spoilage organisms in the dairy industry : a taxonomic study

Raw cow's milk is a product of high nutritional value but this automatically implies it is a medium highly suitable for growth of spoilage organisms that negatively affect milk quality and safety through production of proteolytic and lipolytic enzymes and toxins. Two major groups of spoilage bacteria are recognized, namely pseudomonads and bacilli. Identification of members of these groups is hampered by their confusing taxonomic situation. Both taxa historically grew as dumping grounds for aerobic Gram-positive spore-forming rods in the case of bacilli, and aerobic Gram-negative rods in the case of pseudomonads, resulting in two very large, heterogeneous groups. As a consequence, members of these groups were often poorly identified based on identification tools with insufficient resolution, and usually only two major species were recognized in the issue of milk spoilage, namely Bacillus cereus and Pseudomonas fluorescens. Nonetheless, several studies on the identity of bacterial milk flora indicated diversity was much bigger than originally thought, and the dairy product spoilage issue is clearly not a story of Bacillus cereus and Pseudomonas fluorescens alone. The main objectives of this study were two-fold. The first goal was to accurately map the diversity of bacterial milk flora through a polyphasic identification approach of milk isolates, with focus on bacilli and pseudomonads. Additionally, the spoilage potentials of these isolates were assessed. The second goal was an attempt to resolve the complex taxonomic situation at least for subgroups within the bacilli (the genus Geobacillus) and pseudomonads (the Pseudomonas fluorescens group)

パキスタン由来の重金属耐性を示す新種細菌の単離・同定及びそのバイオレメディエーションや農業への応用の可能性についての研究

学位の種別: 論文博士審査委員会委員 : （主査）東京大学教授 藤原 徹, 東京大学教授 石井 正治, 東京大学教授 妹尾 啓史, 理化学研究所室長 大熊 盛也, National Agricultural Research Center Principal Scientific Officer Iftikhar AhmedUniversity of Tokyo(東京大学

Role of Various Physicochemical Factors in Enhancing Microbial Potential for Bioremediation of Synthetic Dyes

The Indian dye industry is globally recognized for production and export of every known class of dye. On the less attractive side of industrialization, they contribute considerably to environmental pollution. The dyes discarded by industries persist in the environment due to extremely slow rate of biodegradation. Moreover, these dyes are toxic to insects, birds and terrestrial life. The dyes also hamper the light penetration in water bodies, severely affecting the the process of photosynthesis. In spite of the problems associated with synthetic dye disposal, they are industrially preferred due to their fundamental requirement in enhancing overall appearance of goods, quality and cost effectiveness. Several studies have reported physicochemical techniques for remediation of dye effluents. Most of these techniques pose significant drawbacks due to their high energy and cost requirements. The bioremediation approach, on the other hand, offers advantages of sustainable environmental friendly processes to detoxify and degrade dyes into harmless products. This chapter provides an overview of the potential role of various physicochemical factors such as pH, temperature, oxygen and nutrient concentration in optimum decolorization of dyes by naturally isolated microbial strains. In addition, the role of cosubstrates, electron acceptors and microbial enzymes are also discussed

Engineering Parageobacillus thermoglucosidans as a robust platform for bioethanol production

Philosophiae Doctor - PhD (Biotechnology)Parageobacillus thermoglucosidans is a promising “platform” organism to use in the production ofa range of useful metabolites with demonstrated ability to produce ethanol, isobutanol and polylactic acid for bio-degradable plastics. Extensive work has been done in engineering the organism for enhanced ethanol production. However, an often used and highly effective alternative pathway (pyruvate decarboxylase mediated) for ethanol production has not yet been demonstrated in P. thermoglucosidans. We first characterize two novel bacterial pyruvate decarboxylase enzymes (PDC’s) then attempt to express the more thermostable of these enzymes from Gluconobacter oxydans in P. thermoglucosidans to improve ethanol yields. Initial expression was unsuccessful. Analysis of the codon usage pattern for the gene revealed that the codon usage was suboptimal in the heterologous host P. thermoglucosidans. After codon harmonization, we could demonstrate successful expression of the enzyme at 45°C, however not at the bacterium’s optimum growth temperature of 60°C. This was concomitant with enhanced ethanol production close to the theoretical yield possible (0.5g/l)