The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya
Extremophilic microorganisms such as those that thrive in high-salt and high-alkaline environments are promising candidates for the recovery of useful biomaterials including polyhydroxyalkanoates (PHAs). PHAs are ideal alternatives to synthetic plastics because they are biodegradable, biocompatible,...
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| Language: | English |
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MDPI AG
2023-05-01
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| Series: | Bacteria |
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| Online Access: | https://www.mdpi.com/2674-1334/2/2/7 |
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| author | Martin N. Muigano Sylvester E. Anami Justus M. Onguso Godfrey M. Omare |
| author_facet | Martin N. Muigano Sylvester E. Anami Justus M. Onguso Godfrey M. Omare |
| author_sort | Martin N. Muigano |
| collection | DOAJ |
| description | Extremophilic microorganisms such as those that thrive in high-salt and high-alkaline environments are promising candidates for the recovery of useful biomaterials including polyhydroxyalkanoates (PHAs). PHAs are ideal alternatives to synthetic plastics because they are biodegradable, biocompatible, and environmentally friendly. This work was aimed at conducting a bioprospection of bacteria isolated from hypersaline-alkaliphilic lakes in Kenya for the potential production of PHAs. In the present study, 218 isolates were screened by Sudan Black B and Nile Red A staining. Of these isolates, 31 were positive for PHA production and were characterized using morphological, biochemical, and molecular methods. Through 16S rRNA sequencing, we found that the isolates belonged to the genera <i>Arthrobacter</i> spp., <i>Bacillus</i> spp., <i>Exiguobacterium</i> spp., <i>Halomonas</i> spp., <i>Paracoccus</i> spp., and <i>Rhodobaca</i> spp. Preliminary experiments revealed that <i>Bacillus</i> sp. JSM-1684023 isolated from Lake Magadi had the highest PHA accumulation ability, with an initial biomass-to-PHA conversion rate of 19.14% on a 2% glucose substrate. Under optimized fermentation conditions, MO22 had a maximum PHA concentration of 0.516 g/L from 1.99 g/L of cell dry weight and 25.9% PHA conversion, equivalent to a PHA yield of 0.02 g/g of biomass. The optimal PHA production media had an initial pH of 9.0, temperature of 35 °C, salinity of 3%, and an incubation period of 48 h with 2.5% sucrose and 0.1% peptone as carbon and nitrogen sources, respectively. This study suggests that bacteria isolated from hypersaline and alkaliphilic tropical lakes are promising candidates for the production of polyhydroxyalkanoates. |
| first_indexed | 2024-03-11T02:46:36Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2674-1334 |
| language | English |
| last_indexed | 2024-03-11T02:46:36Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Bacteria |
| spelling | doaj.art-3a665fff8d2c416c969978ecaa47fa272023-11-18T09:17:27ZengMDPI AGBacteria2674-13342023-05-0122819710.3390/bacteria2020007The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in KenyaMartin N. Muigano0Sylvester E. Anami1Justus M. Onguso2Godfrey M. Omare3Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, KenyaInstitute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, KenyaInstitute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, KenyaDepartment of Physical and Biological Sciences, Bomet University College, Bomet P.O. Box 701-20400, KenyaExtremophilic microorganisms such as those that thrive in high-salt and high-alkaline environments are promising candidates for the recovery of useful biomaterials including polyhydroxyalkanoates (PHAs). PHAs are ideal alternatives to synthetic plastics because they are biodegradable, biocompatible, and environmentally friendly. This work was aimed at conducting a bioprospection of bacteria isolated from hypersaline-alkaliphilic lakes in Kenya for the potential production of PHAs. In the present study, 218 isolates were screened by Sudan Black B and Nile Red A staining. Of these isolates, 31 were positive for PHA production and were characterized using morphological, biochemical, and molecular methods. Through 16S rRNA sequencing, we found that the isolates belonged to the genera <i>Arthrobacter</i> spp., <i>Bacillus</i> spp., <i>Exiguobacterium</i> spp., <i>Halomonas</i> spp., <i>Paracoccus</i> spp., and <i>Rhodobaca</i> spp. Preliminary experiments revealed that <i>Bacillus</i> sp. JSM-1684023 isolated from Lake Magadi had the highest PHA accumulation ability, with an initial biomass-to-PHA conversion rate of 19.14% on a 2% glucose substrate. Under optimized fermentation conditions, MO22 had a maximum PHA concentration of 0.516 g/L from 1.99 g/L of cell dry weight and 25.9% PHA conversion, equivalent to a PHA yield of 0.02 g/g of biomass. The optimal PHA production media had an initial pH of 9.0, temperature of 35 °C, salinity of 3%, and an incubation period of 48 h with 2.5% sucrose and 0.1% peptone as carbon and nitrogen sources, respectively. This study suggests that bacteria isolated from hypersaline and alkaliphilic tropical lakes are promising candidates for the production of polyhydroxyalkanoates.https://www.mdpi.com/2674-1334/2/2/7isolationscreeningcharacterizationpolyhydroxyalkanoatesPHALake Magadi |
| spellingShingle | Martin N. Muigano Sylvester E. Anami Justus M. Onguso Godfrey M. Omare The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya Bacteria isolation screening characterization polyhydroxyalkanoates PHA Lake Magadi |
| title | The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya |
| title_full | The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya |
| title_fullStr | The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya |
| title_full_unstemmed | The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya |
| title_short | The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya |
| title_sort | isolation screening and characterization of polyhydroxyalkanoate producing bacteria from hypersaline lakes in kenya |
| topic | isolation screening characterization polyhydroxyalkanoates PHA Lake Magadi |
| url | https://www.mdpi.com/2674-1334/2/2/7 |
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