Effectiveness of iodine derived from Eucheuma spinosum against the bacteria Staphylococcus aureus and Salmonella sp.

Seaweed is the primary source of carrageenan


Introduction
Seaweed is one of Indonesia's mainstay seafood commodities.Seaweed cultivation has excellent opportunities for the economic development of coastal communities, and Eucheuma sp. is a seaweed widely cultivated in Madura.(Fatmawati & Wahyudi 2016).It was noted that the potential land for seaweed cultivation is 16,420 ha, and only 372 ha (2.27%) has been utilized.Due to the high demand for industrial raw materials, seaweed cultivation continues to grow today (Priono, 2016).Seaweed Eucheuma sp. is much needed for industry because it has a relatively high carrageenan content.iodine derived from Eucheuma spinosum Another ingredient in Eucheuma sp. is antibacterial compounds, which can be obtained from bioactive compounds through extraction.(Akib et al. 2019;Yusvantika et al. 2022).According to research Santika et al. (2019) The research began by washing Eucheuma spinosum to remove lime and then drying it in the sun to dry.Extraction was done by first grinding 50 g using a blender, followed by maceration using 100 ml chloroform in a ratio of 1:2 (w/v).During the maceration process, the sample was shaken using an orbital rotary shaker for 72 hours at a speed of 120 rpm.The resulting solution is then filtered and heated to separate the pure extract from the solvent.
The iodine concentration was then calculated using titration, with 1% starch solution and 0.1N Na2S2O3 solution.The solution was made by weighing 6.25 g of Na2S2O3 and adding 100 ml of distilled water.Pour into a measuring flask and store in a dark place.Add 1 ml of 0.1N iodine to the homogeneous solution, then add 1% starch until the color changes to brownish yellow + 5 drops.According Slamet & Bambang (2002), measurement of iodine concentration using titration is calculated using the following formula: Bacterial culture media was made by weighing 0.42 mg NA in 15 ml of distilled water at a rate of 28 g per 1000 ml, then putting it in an Erlenmeyer flask tightly covered with aluminum foil so that the NA did not spill (Sakul et al. 2020).The NA media was then sterilized at 121 o C for 30 minutes, and then poured into 5 ml test tubes.Na media production is calculated using the following dilution formula:

Extract rendement Eucheuma spinosum
The rendement of Eucheuma spinosum extract is the result of the extraction process using chloroform solvent (Table 1).Based on research by Maligan et al. (2015), the chloroform solvent was chosen because the chloroform fraction was greater than the yield of other fractions.The yield results indicate that the content of semipolar compounds is greater than polar and nonpolar compounds.(Source: Researcher data, 2022) Table 1 shows that the results of maceration for 72 hours with chloroform solvent obtained a crude extract with a yield of 47%.The chloroform solvent used was 100 ml with a ratio of 1:2 (w/v) (Dhanraj et al. 2009).The extraction method, solvent used, solvent ratio, temperature, and length of maceration time influence the high yield value.The lower temperature will cause a decrease in the yield value.The yield value is high if the temperature during evaporation is constant at 40ºC (Shofikha, 2017).According to research by Mardiyah et al. (2014), every 50 g of seaweed can produce 9.17% crude extract if using ethanol as a solvent.Referring to the research results above, the yield value of the crude extract produced in this research is relatively high.

Iodine levels
Following the extraction of the crude extract, filter paper is used to separate the crude fiber from iodine, resulting in the wet weight.The titration method was used to conduct the iodine concentration test in this study, and the test's findings are shown in Table 2. iodine derived from Eucheuma spinosum The test results as shown in Table 2 show that the color change occurred after adding 4.8 ml of blank liquid.The color change occurs from brownish yellow to clear or colorless.According to research by Linda ( 2018), red seaweed contains iodine at a concentration of 0.1-1%.Based on this range, it shows that the test results in this study (1.22%) were higher than in previous studies.Iodine is produced after the evaporation process.Agustin & Ismiyati (2015) says evaporation is the process of separating the solvent from the pure extract.
Research using evaporation treatment using an oven at 40ºC has been proven to produce relatively high iodine concentrations.
Iodine has polar properties, so that it can dissolve well in chloroform.According to research by Hildianti (2016), stirring for a long time during maceration causes an increase in osmosis between the extracted material and the solvent.This causes dissolution into the Eucheuma spinosum tissue through a screen effect to occur optimally so that the cell glands produce a high concentration of iodine.By measuring the clear zone that developed around the papare disk, which demonstrated that there was inhibitory activity against bacterial growth, the antibacterial activity test findings were determined (Figure 1) The clear zone seen in Figure 1 is evidence of iodine's ability to inhibit the growth of Staphylococcus aureus and Salmonella sp.bacteria.The diameter of the clear zone formed was then measured using a digital caliper, and the results are presented in Table 3.The measurement results showed that the positive control (yodor vex) and negative control (Distilled water) were included in the category of having weak inhibitory power, while iodine from Eucheuma spinosum was included in the strong category in the inhibition test for the bacteria Staphylococcus aureus and Salmonella sp.
The test was carried out by diffusing 10μl of the extract.The antibacterial activity test of Eucheuma spinosum against Staphylococcus aureus based on research by Serment et al. (1970), showed the average diameter of the bacterial inhibition zone was 4.00 mm (200µg=0.2µl), which was included in the weak category.The research results of Rostinawati et al. (2017) stated that the antibacterial activity test on Salmonella sp. with a concentration of 125,000 µl produced an average diameter of the bacterial inhibition zone of 15.20 mm.The results of this research succeeded in proving that iodine derived from Eucheuma spinosum has a strong inhibitory effect on the growth of Staphylococcus aureus and Salmonella sp.bacteria.The concentration of iodine contained in Eucheuma spinosum has the ability to break down bacterial cell walls so that the growth of pathogenic bacteria is inhibited.

Conclusion
The research results prove that iodine derived from Eucheuma spinosum extract has a strong inhibitory effect (11.5 mm) on the activity and growth of the bacteria Staphylococcus aureus and Salmonella sp.
M2 Test of the inhibitory power of Eucheuma spinosum iodine against Staphylococcus aureus and Salmonella sp compared with the control solution (yodor vex).Mattulada et al. (2018) says observations of the activity of bacteria treated with iodine were carried out for 24 hours at a temperature of 37ºC.Haris et al. (2013) says calculation of resistance using the following formula:    = (D1−Dp)+(D2−Dp) 2
The results of the research above demonstrate that natural seaweed extract can inhibit bacterial growth, so this research focuses more on the ability of iodine as an antibacterial, which was tested on Staphylococcus aureus and Salmonella sp..

Table 1 .
Yield of crude extract of Eucheuma spinosum

Table 2 .
Results of iodine concentration calculation

Table 3 .
Results of resistance diameter measuring