Enhanced candicidal compound production by a new soil isolate Penicillium verruculosum MKH7 under submerged fermentation

BMC Microbiology, Dec 2016

Background Microorganisms are a rich source of structurally diverse secondary metabolites that exert a major impact on the control of infectious diseases and other medical conditions. The biosynthesis of these metabolites can be improved by manipulating the nutritional or environmental factors. This work evaluates the effects of fermentation parameters on the production of a lactone compound effective against Candida albicans by Penicillium verruculosum MKH7 under submerged fermentation. Design–Expert version8.0 software was used for construction of the experimental design and statistical analysis of the experimental data. Results The important factors influencing antibiotic production selected in accordance with the Plackett–Burman design were found to be initial pH, temperature, peptone, MgSO 4 .7H 2 O. Orthogonal central composite design and response surface methodology were adopted to further investigate the mutual interaction between the variables and identify the optimum values that catalyse maximum metabolite production. The determination coefficient (R 2 ) of the fitted second order model was 0.9852. The validation experiments using optimized conditions of initial pH 7.4, temperature 27 °C, peptone 9.2 g/l and MgSO 4 .7H 2 O 0.39 g/l resulted in a significant increase (almost 7 fold from 30 to 205.5 mg/l) in the metabolite production which was in agreement with the prediction (211.24 mg/l). Stability of the compound was also assessed on the basis of its response to physical and chemical stresses. Conclusions So far as our knowledge goes, till date there are no reports available on the production of antibiotics by Penicillium verruculosum through media optimization using RSM. Optimization not only led to a 7 fold increase in metabolite yield but the same was achieved at much lesser time (8–10 days compared to the earlier 12–15 days). The enhanced yield of the antibiotic strongly suggests that the fungus P. verruculosum MKH7 can be efficiently used for antibiotic production on a large scale.

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Enhanced candicidal compound production by a new soil isolate Penicillium verruculosum MKH7 under submerged fermentation

Talukdar et al. BMC Microbiology Enhanced candicidal compound production by a new soil isolate Penicillium verruculosum MKH7 under submerged fermentation Shruti Talukdar 0 Madhumita Talukdar 0 Manorama Buragohain 0 Archana Yadav 0 R. N. S. Yadav 1 T. C. Bora 0 0 Biotechnology Division, CSIR-North-East Institute of Science & Technology , Jorhat 785006, Assam , India 1 Department of Life Sciences, Dibrugarh University , Dibrugarh 786004, Assam , India Background: Microorganisms are a rich source of structurally diverse secondary metabolites that exert a major impact on the control of infectious diseases and other medical conditions. The biosynthesis of these metabolites can be improved by manipulating the nutritional or environmental factors. This work evaluates the effects of fermentation parameters on the production of a lactone compound effective against Candida albicans by Penicillium verruculosum MKH7 under submerged fermentation. Design-Expert version8.0 software was used for construction of the experimental design and statistical analysis of the experimental data. Results: The important factors influencing antibiotic production selected in accordance with the Plackett-Burman design were found to be initial pH, temperature, peptone, MgSO4.7H2O. Orthogonal central composite design and response surface methodology were adopted to further investigate the mutual interaction between the variables and identify the optimum values that catalyse maximum metabolite production. The determination coefficient (R2) of the fitted second order model was 0.9852. The validation experiments using optimized conditions of initial pH 7. 4, temperature 27 °C, peptone 9.2 g/l and MgSO4.7H2O 0.39 g/l resulted in a significant increase (almost 7 fold from 30 to 205.5 mg/l) in the metabolite production which was in agreement with the prediction (211.24 mg/l). Stability of the compound was also assessed on the basis of its response to physical and chemical stresses. Conclusions: So far as our knowledge goes, till date there are no reports available on the production of antibiotics by Penicillium verruculosum through media optimization using RSM. Optimization not only led to a 7 fold increase in metabolite yield but the same was achieved at much lesser time (8-10 days compared to the earlier 12-15 days). The enhanced yield of the antibiotic strongly suggests that the fungus P. verruculosum MKH7 can be efficiently used for antibiotic production on a large scale. - Background Fungal infections have increased dramatically over the last few decades and this rise in the number of opportunistic fungal infections has stimulated research towards the development of novel antifungal agents [1]. Currently the fourth most common cause of nosocomial infection is the Candida species [2]. Notorious among all the Candida species is the Candida albicans [3]. Microbes are one of the most productive sources of natural products from which antibiotics are derived [4]. Fungi, particularly the filamentous ones, are highly potential reservoirs of products with excellent antagonistic activity against human pathogens [5]. A variety of secondary metabolites including antimicrobial substances is reported to have been produced by the fermentation of Penicillium species [6–8]. Their production depends upon the nutrition and cultivation conditions of the strains [9]. The nutritional requirements and physical parameters can be managed and controlled to increase the productivity of microbial metabolites [10]. However, these processes are usually quite long and arduous when © The Author(s). 2016 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. accomplished using routine techniques such as a onefactor-at-a-time method [11]. In any optimization process, first the screening of the important variables has to be done and subsequently estimation of optimal levels of these factors [12]. Statistical methods are quite advantageous with reference to a rapid identification of the significant factors and also decrease in the total number of experiments [13–16]. Application of statistical methods like Plackett–Burman design (PBD) and response surface methodology (RSM) in process optimization have been reported [17, 18]. The shortcomings of conventional methods have been eliminated by RSM [19–21]. RSM is a fast and effective tool as it reduces the number of experimental trials and also helps to compare the significance of a number of variab (...truncated)


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Shruti Talukdar, Madhumita Talukdar, Manorama Buragohain, Archana Yadav, R. Yadav, T. Bora. Enhanced candicidal compound production by a new soil isolate Penicillium verruculosum MKH7 under submerged fermentation, BMC Microbiology, 2016, pp. 288, 16, DOI: 10.1186/s12866-016-0713-8