20 th LACCEI International Multi-Conference for Engineering, Education, and Technology: “Education, Research and Leadership in Post-pandemic Engineering: Resilient, Inclusive and Sustainable Actions”, Hybrid Event, Boca Raton, Florida- USA, July 18 - 22, 2022. 1 MALDI-TOF MS for the identification of bacteria from Acropora cervicornis samples with White Band Disease Mary Andrea Fennix-Agudelo 1 Facultad de Ciencias Básicas, Universidad Tecnológica de Bolívar Cartagena de Indias-Bolívar, Colombia. Esteban Zarza-González 2 Escuela de Biología Marina, Universidad del Sinú Cartagena de Indias-Bolívar, Colombia. Zilpa Adriana Sánchez-Quitian 3 Departamento de Biología y Microbiología Universidad de Boyacá. Tunja-Colombia. Nuri Merchán-Castellanos 4 P rograma de Bioingeniería, Universidad El Bosque Bogotá-Colombia. Juan Carlos Martinez-Santos 5 Facultad de Ingeniería, Universidad Tecnológica de Bolívar Cartagena de Indias-Bolívar, Colombia. Claudia Marcela Parra-Giraldo 6 Unidad de Investigación en Proteómica y Micosis Humanas, Pontificia Universidad Javeriana Bogotá-Colombia Edisson Chavarro-Mesa 7 Facultad de Ciencias Básicas, Universidad Tecnológica de Bolívar Cartagena de Indias-Bolívar, Colombia. echavarro@utb.edu.co Abstract — White Band Disease (WBD) is one of the most harmful coral syndromes in the Caribbean, de teriorating the structure of many corals during the eighties and nineties. Since its etiology is not entirely known, the use of techniques aimed at identifying the associated agents could provide an approach to the composition of the populations involved in the deterioration of A. cervicornis. Therefore, this research's objective was to isolate and characterize bacteria associated with WBD in A. cervicornis from hanging nurseries of Rosario and San Bernardo Corals National Natural Park, Colombia, using MALDI-TOF MS and PCR. The results showed the presence of Bacillus cereus bacteria in individuals with bleaching signs from nurseries and transplant areas on Isla Tesoro and Isla Ceiner. One of these strains sequenced and phylogenetically analyzed was closely related to Bacillus thuringiensis, with similarities of up to 99%. The presence of B. cereus could indicate a special relationship between this microorganism and WBD. However, it is imperative to carry out more studies on identifying the bacteria associated with this disease to support these findings. Keywords — Coastal ecosystems, coral disease, coral nursery. I. INTRODUCTION Coral reefs are considered one of the most intricate and varied ecosystems on the planet, of great ecological importance given their role as home to almost a third of the marine species discovered [1]. Coral diseases, being listed as one of the main sources of mortality of these specimens, are defined as changes, either temporary or persistent, in the physical characteristics of the affected individual. However, the etiology of many diseases is difficult to determine, given the great diversity of microorganisms that their holobiont naturally harbors [2] In the Caribbean, during the 1980s and 1990s, white band disease (BBD) caused notable losses in the genus Acropora, contributing to the deterioration of the structural complexity of reefs in this area [3]. The cause is not fully identified, nor has it been proven to be the same in Acropora species. However, there are multiple candidates associated with this syndrome [4]. On the other hand, lesions with a pattern similar to this condition appear in hanging nurseries of Acropora cervicornis in the Parque Nacional Natural Corales del Rosario y San Bernardo (PNNCRSB), Colombia [5]. Then, the need arises to develop a system that allows the recognition of its causative agents from changes in the composition of the holobiont. Additionally, Matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry (MALDI-TOF MS) is an analytical technique based on the detection of specific ribosomal proteins at the level of genus, species, or bacterial subgroup [6], [7]. Hence, MALDI-TOF MS has been considered a promising technology in the identification of isolates of marine origin, obtaining results hours after culture, given its ability to analyze whole bacterial cells, and requiring little sample preparation time, which increases its cost- effectiveness [8], [9]. In this context, the definition of the associated microorganisms of this syndrome would allow taking measures that can guarantee their survival in the natural environment, which would contribute significantly to the restoration of ecological integrity, and preservation of the ecosystem services they provide. Thus, through the implementation of MALDI- TOF MS and amplification of species-specific genes, this project will seek to provide information related to the microbial communities present in A. cervicornis corals with visible signs of WBD in hanging nurseries. II. MET HODOLOGY A. Collection of biological material ANLA (National Environmental Licensing Authority) permitted collecting a total of forty-nine A. cervicornis fragments. The samples, collected on November 3, 2018, were taken at five PNNCRSB points: the Isla Tesoro (T) and Isla Ceiner (O) coral nurseries; the coral transplant area of each nursery (TT and OT), and an area with specimens in the wild Digital Object Identifier (DOI): http://dx.doi.org/10.18687/LACCEI2022.1.1.714 ISBN: 978-628-95207-0-5 ISSN: 2414-6390