The unknown bacteria under test is Micrococcus roseus.
Related Article: Some biological activities of pigments extracted from Micrococcus roseus (PTCC 1411) and Rhodotorula glutinis (PTCC 5257)
Link to the article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5806839/
Summary
This article emphasizes on the need to phase out the synthetic pigments used in food industry with their natural equivalents extracted from various micro-organisms. Thus, the example organisms used in this case are Rhodotorula glutinis and Micrococcus roseus ( Rostami et al., 2016) . The anti-cancerous, antioxidant, anti-inflammatory and antimicrobial properties of specific pigment extracted from these organisms were evaluated.
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According to this article, carotenoids are among the most studied of these pigments owing to their significance in food preservation. Moreover, this pigment offers verified health benefits to human beings for its antioxidant effects, anti-inflammatory effects, antimicrobial and as a precursor of vitamin A ( Rostami et al., 2016) . An understanding of this pigment is also vital to addressing microbial contamination, food sensitivity and inflammation, and some chronic cancers.
The Persian Type Culture Collection method was used to collect Rhodotorula glutinis and Micrococcus roseus. The cultures were subjected to ideal conditions of pH, glucose, yeast, temperature and incubation duration for maximum harvesting of the organisms ( Rostami et al., 2016) . The collected micro-organisms were centrifuged and spectrophotometric analysis conducted to measure total carotenoid (TC).
The collected carotenoid was assayed against various microorganisms such as Bacillus cereus, Streptococcus pyogenes and Escherichia coli and their impacts on various elements recorded.
The disk diffusion (Kirby-Baeur) method was used to evaluate the antimicrobial activity of the extracts on the microorganisms while the agar dilution method was employed to determine the minimum inhibitory (MIC), fungicidal (MFC) and bactericidal (MBC) concentration ( Rostami et al., 2016) .
The radical scavenging activity procedure helped in determining the antioxidant properties of the extracts. The researchers also performed the beta-carotene bleaching test using spectrophotometer and bovine-brain peroxidation tests using thiobarbituric acid( Rostami et al., 2016) . Other tests included anti-cancer activity, anti-inflammatory activity and in-vivo carcinogenesis.
The study established that carotenoid extracts from Rhodotorula glutinis and Micrococcus roseus had several benefits on human bodies. However, these benefits differed slightly depending on the source of the extract. For example, gram-positive bacteria showed greater antibacterial effects that gram-negative bacteria.
References
Rostami, H., Hamedi, H., & Yolmeh, M. (2016). Some biological activities of pigments extracted from Micrococcus roseus (PTCC 1411) and Rhodotorula glutinis (PTCC 5257). International journal of immunopathology and pharmacology , 29 (4), 684–695. https://doi.org/10.1177/0394632016673846
Appendix: Identification of Unknown Organism.
| organism | Gram | Shape |
BCP GLUC. |
BCP LAC. |
BCP MALT. |
BCP MAN. |
BCP SUC. |
gelatin | Urease |
H 2 S |
Indole | Methyl Red | V-P** | Citrate | Oxidase | Catalase | Motility |
| Alcaligenes faecalis | - | R | - | - | - | - | - | - | - | - | - | - | - | + | + | + | + |
| Bacillus cereus | + | R | A | - | A | - |
A |
+ | - | - | - | + | - | +(w) | + | +(w) | + |
| Bacillus subtilis | + | R | A | - | A | - |
A |
+ | - | - | - | - | + | + | + | + | + |
| Citrobacter freundii | - | R | A/G | A/G | A/G | A/G | A/G | - | - | + | - | + | - | + | - | - | + |
| Enterobacter aerogenes | - | R | A/G | A/G | A/G | A/G | A/G | - | - | - | - | - | + | + | - | + | + |
| Escherichia coli | - | R | A/G | A/G | A/G | A/G | - | - | - | - | + | +(w) | - | - | - | + | + |
| Enterococcus faecalis | + | C | A | A | A | A | A | - | - | - | - | + | - | - | - | - | - |
| Klebsiella pneumoniae | - | R | A/G | A/G | A/G | A/G | A/G | - | +(w) | - | - | + | - | + | - | + | - |
| Micrococcus luteus | + | C | - | - | - | - | - | - | + | - | - | - | - | - | + | + | - |
| Micrococcus roseus | + | C | - | - | - | - | - | - | - | - | - | - | - | - | - | + | - |
| Moraxella catarrhalis | - | C | - | - | - | - | - | - | - | - | - | - | - | - | + | + | - |
| Morganella morganii | - | R | A/G | - | - | - | - | - | + | - | + | + | - | - | - | + | + |
| Mycobacterium phlei | + (v) | R | - | - | - | - | - | - | +(s) | - | - | - | - | - | - | + | - |
| Mycobacterium smegmatis | + (v) | R | - | - | - | - | - | - | - | - | - | - | - | - | - | +(w) | - |
| Proteus mirabilis | - | R | A/G $ | - | A/G $ | - | - | + | + | + | - | + | - | +(s) | - | + | + |
| Proteus vulgaris | - | R | A/G $ | - | A/G $ | - | A/G $ | - | + | + | + | + | - | - | - | + | + |
| Pseudomonas aeruginosa | - | R | - | - | - | - | - | + | - | - | - | - | - | + | + | + | + |
| Serratia marcescens © | - | R | A | - | A | A | A | + | - | - | - | - | + | + | - | + | + |
| Staphylococcus aureus | + | C | A | A | A | A | A | - | - | - | - | + | + | - | - | + | - |
| Staphylococcus epidermidis | + | C | A | A | A | - | A | - | - | - | - | + | - | - | +(w) | + | - |
| Salmonella enteritidis | - | R | A/G | - | A/G | A/G | - | - | - | + | - | + | - | + | - | + | + |
| Shigella flexneri | - | R | A |
|
A | A | - | - | - | - | - | + | - | - | - | + | - |
CHART SYMBOL KEY:
+ = positive A = Acid (v) =may be non-reactive (expect possibly light purple instead of dark ☺) © = grows well at 37 o w/o obvious pigmentation
- = negative G = Gas **VP + may take 30-60 minutes to develop
R = Rod A/G= Acid AND Gas
C = Coccus A/G $ =Acid and Gas, OR just Acid (READ THIS CAREFULLY)
(s) = slow (incubate 1 or 2 days beyond the recommended incubation time)
(w) = weak (usual incubation time but not a strong positive)
SDSU SUMMARY OF BIOCHEMICAL TESTS FOR UNKNOWN revised 5/14/20 Perez
