Volume 56, Issue No. 2

    https://doi.org/10.17113/ftb.56.02.18.5593 

Acetic Acid Bacteria in the Food Industry: Systematics, Characteristics and Applications

Rodrigo José Gomes¹, Maria de Fatima Borges², Morsyleide de Freitas Rosa², Raúl Jorge Hernan
Castro-Gómez¹ and Wilma Aparecida Spinosa¹*

¹Department of Food Science and Technology, State University of Londrina, Celso Garcia Cid (PR 445) Road, 86057-970 Londrina, PR, Brazil
²Embrapa Tropical Agroindustry, 2270 Dra. Sara Mesquita Road, 60511-110 Fortaleza, CE, Brazil

Article history:
Received: 6 November 2017
Accepted: 30 January 2018

Key words:
acetic acid bacteria, taxonomy, vinegar, bacterial cellulose, biotechnological products

Summary:
The group of Gram-negative bacteria capable of oxidising ethanol to acetic acid is called acetic acid bacteria (AAB). They are widespread in nature and play an important role in the production of food and beverages, such as vinegar and kombucha. The ability to oxidise ethanol to acetic acid also allows the unwanted growth of AAB in other fermented beverages, such as wine, cider, beer and functional and soft beverages, causing an undesirable sour taste. These bacteria are also used in the production of other metabolic products, for example, gluconic acid, l-sorbose and bacterial cellulose, with potential applications in the food and biomedical industries. The classification of AAB into distinct genera has undergone several modifications over the last years, based on morphological, physiological and genetic characteristics. Therefore, this review focuses on the history of taxonomy, biochemical aspects and methods of isolation, identification and quantification of AAB, mainly related to those with important biotechnological applications.

*Corresponding author:    +554333714585 
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    https://doi.org/10.17113/ftb.56.02.18.5393 

Bioprospecting for Genes Encoding Hydrocarbon-Degrading Enzymes from Metagenomic Samples Isolated from Northern Adriatic Sea Sediments

Ranko Gacesa^1,2,3#, Damir Baranasic^1,4#, Antonio Starcevic^1,5, Janko Diminic^1,5, Marino Korlević⁶, Mirjana Najdek⁶, Maria Blažina⁶, Davor Oršolić¹, Domagoj Kolesarić¹, Paul F. Long^2,3, John Cullum⁴, Daslav Hranueli^1,5, Sandi Orlic^7,8 and Jurica Zucko^1,5*

¹Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia
²Institute of Pharmaceutical Science King’s College London, Franklin-Wilkins Building, Stamford Street, London SE1 9NH, UK
³Department of Chemistry, King’s College London, Franklin-Wilkins Building, Stamford Street, London SE1 9NH, UK
⁴Department of Genetics, University of Kaiserslautern, Postfach 3049, DE-67653 Kaiserslautern, Germany
⁵Centre of Research Excellence for Marine Bioprospecting - BioProCro, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
⁶Centre for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, HR-52210 Rovinj, Croatia
⁷Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
⁸Center of Excellence for Science and Technology Integrating Mediterranean Region, Microbial Ecology, HR-10000 Zagreb, Croatia

Article history:
Received: 16 June 2017
Accepted: 12 February 2018

Key words:
oil pollution, n-alkane degradation, database

Summary:
Three metagenomic libraries were constructed using surface sediment samples from the northern Adriatic Sea. Two of the samples were taken from a highly polluted and an unpolluted site respectively. The third sample from a polluted site had been enriched using crude oil. The results of the metagenome analyses were incorporated in the REDPET relational database (http://redpet.bioinfo.pbf.hr/REDPET), which was generated using the previously developed MEGGASENSE platform. The database includes taxonomic data to allow the assessment of the biodiversity of metagenomic libraries and a general functional analysis of genes using hidden Markov model (HMM) profiles based on the KEGG database. A set of 22 specialised HMM profiles was developed to detect putative genes for hydrocarbon-degrading enzymes. Use of these profiles showed that the metagenomic library generated after selection on crude oil had enriched genes for aerobic n-alkane degradation. The use of this system for bioprospecting was exemplified using potential alkB and almA genes from this library.

*Corresponding author:    +38514605151
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^#These authors contributed equally to this work

     https://doi.org/10.17113/ftb.56.02.18.5547 

Recent Trends in Biodiesel and Biogas Production

Arijana Bušić¹, Semjon Kundas², Galina Morzak³, Halina Belskaya³, Nenad Marđetko¹, Mirela Ivančić Šantek¹, Draženka Komes¹, Srđan Novak¹ and Božidar Šantek^1*

¹University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia
²Belarussian National Technical University, Power Plant Construction and Engineering Services Faculty, Nezavisimosti Ave. 150, BY-220013 Minsk, Belarus
³Belarussian National Technical University, Mining Engineering and Engineering Ecology Faculty, Nezavisimosti Ave. 65, BY-220013 Minsk, Belarus

Article history:
Received: 2 October 2017
Accepted: 26 February 2018

Key words:
biodiesel, biogas, microbial lipids, transesterification, anaerobic digestion, recovery and purification

Summary:
Biodiesel and biogas are two very important sources of renewable energy worldwide, and particularly in the EU countries. While biodiesel is almost exclusively used as transportation fuel, biogas is mostly used for production of electricity and heat. The application of more sophisticated purification techniques in production of pure biomethane from biogas allows its delivery to natural gas grid and its subsequent use as transportation fuel. While biogas is produced mostly from waste materials (landfills, manure, sludge from wastewater treatment, agricultural waste), biodiesel in the EU is mostly produced from rapeseed or other oil crops that are used as food, which raises the ‘food or fuel’ concerns. To mitigate this problem, considerable efforts have been made to use non-food feedstock for biodiesel production. These include all kinds of waste oils and fats, but recently more attention has been devoted to production of microbial oils by cultivation of microorganisms that are able to accumulate high amounts of lipids in their biomass. Promising candidates for microbial lipid production can be found among different strains of filamentous fungi, yeast, bacteria and microalgae. Feedstocks of interest are agricultural waste rich in carbohydrates as well as different lignocellulosic raw materials where some technical issues have to be resolved. In this work, recovery and purification of biodiesel and biogas are also considered.

*Corresponding author:    +38514605290
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