Characterization of Actinobacteria Degrading and Tolerating Organic Pollutants

Species of the genera Rhodococcus, Gordonia and Mycobacterium are known as degraders of recalcitrant pollutants. These bacteria are good survivors in harsh environments. Due to such properties these organisms are able to occupy a wide range of environmental niches. The members of these taxa have been suggested as tools for biotechnical applications such as bioremediation and biosynthesis. At the same time several of the species are known as opportunistic human pathogens. Therefore, the detailed characterization of any isolate that has potential for biotechnological applications is very important. This thesis deals with several corynebacterial strains originating from different polluted environments: soil, water-damaged indoor walls, and drinking water distribution systems. A polyphasic taxonomic approach was applied for characterization of the isolates. We found that the strains degrading monoaromatic compounds belonged to Rhodococcus opacus, a species that has not been associated with any health problem. The taxonomic position of strain B293, used for many years in degradation research under different names, was clarified. We assigned it to the species Gordonia polyisoprenivorans. This species is classified under European Biohazard grouping 1, meaning that it is not considered a health hazard for humans. However, there are reports of catheter-associated bacteraemia caused by G. polyisoprenivorans. Our results suggested that the ability of the organism to grow on phthalate esters, used as softeners in medical plastics, may be associated with the colonization of catheters and other devices. In this thesis Mycobacterium lentiflavum, a new emerging opportunistic human pathogen, was isolated from biofilms growing in public drinking water distribution systems. Our report on isolation of M. lentiflavum from water supplies is the second report on this species from drinking water systems, which may thus constitute a reservoir of M. lentiflavum. Automated riboprinting was evaluated for its applicability in rapidly identifying environmental mycobacteria. The technique was found useful in the characterization of several species of rapidly and slowly growing environmental mycobacteria. The second aspect of this thesis refers to characterization of the degradation and tolerance power of several R. opacus, M. murale and G. polyisoprenivorans strains. R. opacus GM-14 utilizes a wide range of aromatic substrates, including benzene, 15 different halobenzenes, 18 phenols and 7 benzoates. This study revealed the high tolerance of R. opacus strains toward toxic hydrophobic compounds. R. opacus GM-14 grew in mineral medium to which benzene or monochlorobenzene was added in amounts of 13 or 3 g l-1, respectively. R. opacus GM-29 utilized toluene and benzene for growth. Strain GM-29 grew in mineral medium with 7 g l-1 of liquid toluene or benzene as the sole carbon source, corresponding to aqueous concentrations of 470 and 650 mg l-1, respectively. Most organic solvents, such as toluene and benzene, due to their high level of hydrophobicity, pass through the bacterial membrane, causing its disintegration. In this thesis the mechanisms of adaptation of rhodococci to toxic hydrophobic compounds were investigated. The rhodococcal strains increased the level of saturation of their cellular fatty acids in response to challenge with phenol, chlorophenol, benzene, chlorobenzene or toluene. The results indicated that increase in the saturation level of cellular fatty acids, particularly that in tuberculostearic acid, is part of the adaptation mechanism of strains GM-14 and GM-29 to the presence of toxic hydrophobic compounds

Characterization of Microbiological Quality of Whole and Gutted Baltic Herring

There is growing interest in Baltic herring (Clupea harengus membras) and other undervalued, small-sized fish species for human consumption. Gutting or filleting of small-sized fish is impractical; hence, the aim of this study was to explore the suitability of the whole (ungutted) herring for food use. The microbiological quality of commercially fished whole and gutted herring was analysed with culture-dependent methods combined with identification of bacterial isolates with MALDI-TOF Mass Spectrometry and culture-independent 16S rRNA gene amplicon sequencing. Whole and gutted herring had between 2.8 and 5.3 log(10) CFU g(−1) aerobic mesophilic and psychrotrophic bacteria and between 2.2 and 5.6 log(10) CFU g(−1) H₂S-producing bacteria. Enterobacteria counts remained low in all the analysed herring batches. The herring microbiota largely comprised the phyla Proteobacteria, Firmicutes, and Actinobacteria (71.7% to 95.0%). Shewanella, Pseudomonas, and Aeromonas were the most frequently isolated genera among the viable population; however, with the culture-independent approach, Shewanella followed by Psychrobacter were the most abundant genera. In some samples, a high relative abundance of the phylum Epsilonbacteraeota, represented by the genus Arcobacter, was detected. This study reports the bacterial diversity present in Baltic herring and shows that the microbiological quality was acceptable in all the analysed fish batches

PENGGUNAAN HIDROLISAT JERAMI PADI (Oryza sativa Linn) SEBAGAI BAHAN DASAR PRODUKSI BIOPLASTIK POLI(3-HIDROKSIBUTIRAT) DENGAN MENGGUNAKAN BAKTERI Bacillus cereus

Jerami padi merupakan limbah biomasssa berselulosa yang berlimpah, dan belum banyak dimanfaatkan. Pada penelitian ini, jerami padi digunakan sebagai sumber karbon dalam fermentasi bakteri untuk produksi biopolimer poli(3-hidroksibutirat), P(3HB). Jerami padi diubah menjadi bentuk hidrolisat menggunakan enzim selulase yang diproduksi oleh fungi Trichoderma viride. Hidrolisat dengan konsentrasi 20, 40, 60, 80 % difermentasi menggunakan inokulum bakteri Bacillus cereus dengan konsentrasi 1, 5, dan 10 %. Kandungan P(3HB) dalam biomassa ditentukan dengan kromatografi gas. Hasil menunjukkan biomassa tertinggi yaitu sebesar 84 mg/100mL pada konsentrasi hidrolisat jerami padi 80% dan inokulum 10%. Kandungan P(3HB) tertinggi dihasilkan sebesar 75,8% pada konsentrasi hidrolisat jerami padi 60% dan inokulum 10%. Kata kunci: jerami padi, fermentasi, poli(3-hidroksibutirat

A Small In Vitro Fermentation Model for Screening the Gut Microbiota Effects of Different Fiber Preparations

The development of prebiotic fibers requires fast high-throughput screening of their effects on the gut microbiota. We demonstrated the applicability of a mictotiter plate in the in vitro fermentation models for the screening of potentially-prebiotic dietary fibers. The effects of seven rye bran-, oat- and linseed-derived fiber preparations on the human fecal microbiota composition and short-chain fatty acid production were studied. The model was also used to study whether fibers can alleviate the harmful effects of amoxicillin-clavulanate on the microbiota. The antibiotic induced a shift in the bacterial community in the absence of fibers by decreasing the relative amounts of Bifidobacteriaceae, Bacteroidaceae, Prevotellaceae, Lachnospiraceae and Ruminococcaceae, and increasing proteobacterial Sutterilaceae levels from 1% to 11% of the total microbiota. The fermentation of rye bran, enzymatically treated rye bran, its insoluble fraction, soluble oat fiber and a mixture of rye fiber:soluble oat fiber:linseed resulted in a significant increase in butyrate production and a bifidogenic effect in the absence of the antibiotic. These fibers were also able to counteract the negative effects of the antibiotic and prevent the decrease in the relative amount of bifidobacteria. Insoluble and soluble rye bran fractions and soluble oat fiber were the best for controlling the level of proteobacteria at the level below 2%

PERBANDINGAN PERFORMA KOLEKTOR SURYA POINT PARABOLIC CONCENTRATING ANTARA REFLEKTOR ALUMINIUM FOIL DAN REFLEKTOR CERMIN KACA

Aluminium foil merupakan reflektor yang sering digunakan pada penelitian kolektor surya, salah satunya pada kolektor surya poin parabolic concentrating. Namun efisisensi yang dihasilkan masih kecil sehingga dikembangkan penggunaan cermin kaca sebagai reflektor. Namun, pada pengujian sebelumnya tidak ada variable control yang jelas sehingga performa antara kedua reflektor kolektor surya tersebut tidak dapat dibandingkan. Oleh sebab itu, untuk mengetahui reflektor yang memiliki performa paling baik diperlukan penelitian dengan membandingkan kolektor surya reflektor aluminium foil dengan reflektor cermin kaca. Untuk mengetahui performa kolektor surya, pada penelitian ini dilakukan dengan metode eksperimen, dimana kolektor surya divariasikan menggunakan reflektor aluminium foil dan reflektor cermin kaca. Pengujian dilakukan pada pukul 10.00 WIB sampai pukul 14.00 WIB dengan interval 25 menit selama 3 hari. Pada penelitian yang telah dilakukan, didapatkan hasil bahwa perubahan temperatur kolektor surya reflektor cermin kaca lebih tinggi dibandingkan reflektor aluminium foil. Begitu juga dengan efisiensi yang didapatkan, kolektor surya reflektor cermin kaca memiliki efisiensi tertinggi 87,11%, sedangkan pada kolekor surya reflektor aluminium foil memiliki efisiensi tertinggi sebesar 59,75%. Dari percobaan yang telah dilakukan dapat disimpulkan bahwa kolektor surya reflektor cermin kaca lebih baik dari pada kolektor surya reflektor aluminium foil. Kata Kunci: kolektor surya, reflektor aluminium foil, reflektor cermin kaca, temperatur, efisiens

Chicory Extracts and Sesquiterpene Lactones Show Potent Activity against Bacterial and Fungal Pathogens

Chicory (Cichorium intybus L.) is an important industrial crop cultivated mainly to extract the dietary fiber inulin. However, chicory also contains bioactive compounds such as sesquiterpene lactones and certain polyphenols, which are currently discarded as waste. Plants are an important source of active pharmaceutical ingredients, including novel antimicrobials that are urgently needed due to the global spread of drug-resistant bacteria and fungi. Here, we tested different extracts of chicory for a range of bioactivities, including antimicrobial, antifungal and cytotoxicity assays. Antibacterial and antifungal activities were generally more potent in ethyl acetate extracts compared to water extracts, whereas supercritical fluid extracts showed the broadest range of bioactivities in our assays. Remarkably, the chicory supercritical fluid extract and a purified fraction thereof inhibited both methicillin-resistant Staphylococcus aureus (MRSA) and ampicillin-resistant Pseudomonas aeruginosa IBRS P001. Chicory extracts also showed higher antibiofilm activity against the yeast Candida albicans than standard sesquiterpene lactone compounds. The cytotoxicity of the extracts was generally low. Our results may thus lead to the development of novel antibacterial and antifungal preparations that are both effective and safe for human use

Electrochemically generated biocides for controlling contamination in papermaking

Feasibility of electrochemically generated biocides in papermaking was evaluated in pilot scale trials. The trials indicated that electrochemically generated biocides prevent microbial growth and proliferation in broke systems, as well as in water circulations. The spoilage of broke can be delayed, and already spoiled broke can be recovered using these biocides. The improved broke quality increases the stability of the paper machine and, consequently, less broke is produced. The biocides can be added to water or pulp, and they have hardly any negative effect on the process or the end product. The presence of reducing compounds may cause limitations in the use of these oxidative biocides. It was observed that electrochemically generated biocide was also efficient against heat-resistant spores. However, the biocide was less efficient against spores as compared to vegetative cells, both aerobic and anaerobic, especially when the spore numbers were higher than 104 cfu/ml. Onsite oxidant production eliminates the transportation and storage of biocides. Moreover, due to the short time between the production and use, the degradation of the active compounds can be minimized