ENHANCEMENT OF IAA PRODUCTION FROM Rhizobium pusense THROUGH ADDITION OF TRYPTOPHAN PRECURSORS FROM SHEEP MANURE AND ELECTRICAL VOLTAGE INDUCTION

• Main Author: Latifa, Dian
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/41225
• Institution: Institut Teknologi Bandung

Fitohormones are organic compounds which in small amounts can influence the growth and development of plant. One type of phytohormone that is widely used in agriculture is auxin. The need for auxin in Indonesia is high but its ability to produce is low, so that Indonesia have to import synthetic auxin from abroad. Besides being expensive, synthetic auxin also has the potential to pollute the environment. Therefore, exploration for biological sources capable of producing natural auxin has done. One of potential biological sources is the bacterium Rhizobium pusense. The potential of Rhizobium bacteria to produce plant hormones, namely IAA has been proven by several previous studies. The amount of IAA production in these bacteria can be increased through electrical voltage optimization which is first made by substituting synthetic tryptophan using sheep manure. The combination of these two treatments is expected to be able to produce high amounts of IAA but it’s more efficient than the control and treatment of electrical stress combined with synthetic tryptophan. The first step taken in this study was to find the best amount of sheep manure to add to the medium with the aim of producing IAA. The number of added sheep manure was 1g/l, 3g/l, 5g/l, 7g/l, and 9g/l and combined with liquid luria bertani medium. Information obtained in one gram of sheep manure contains as much as 9.7 mg/g tryptophan. Addition of 9 g/l sheep manure equivalent to 87.5 ppm synthetic tryptophan was able to produce IAA as much as 22.07 ppm on the second day of production time. It can be concluded that the more addition of sheep manure as a source of IAA precursors in the form of tryptophan, the higher the amount of IAA produced. Further optimization of physical factors in the form of electric current stress with AC voltage 3V, 6V, 9V, 12V, 15V and 18V for 5 seconds, 10 seconds and 15 seconds in luria bertani medium that added synthetic tryptophan medium 87.5 ppm or equivalent to 9gr / l sheep manure in each treatment. Based on the results, the 6 volt treatment for 15 seconds combined with tryptophan 87.5 ppm was the best treatment in producing IAA of 68.5 ppm produced on the fourth day of production. The ANOVA test and Duncan's advanced test showed that the treatment of 6 volt for 5 seconds with 87.5 ppm synthetic tryptophan supplementation showed a significant difference with the control. After getting the best treatment using synthetics, substituted the amount of synthetic tryptophan to the amount of sheep manure so that experiments with 6 volt 5 seconds electric voltage were carried out with 9 g / l supplementation of sheep manure. This treatment produced the highest IAA results of 36.42 ppm on the fourth day. Based on these data, it is known that the cost of IAA production from the combination treatment of using electric voltage using sheep manure is 611.64 rupiah more expensive when compared to using synthetic tryptophan which is induced by electric voltage but 1198.37 rupiah less than control on a laboratory scale. In addition, to anticipate large-scale production, without using synthetic tryptophan or media, cheap production has done used only 9g / l sheep manure and produced 6.21 ppm IAA on the sixth day with a production cost of 117.03 rupiah per ppm. This cost is about 8 times cheaper than the price of pure IAA on the market which is 1,000 rupiah perpm. Proof of IAA produced using Rhizobium pusense bacteria can affect plants by inducing them on mung bean sprouts that are 2 days old and then planted on the ground for 7 days. The results obtained were IAA produced by these bacteria can stimulate plant growth and root growth significantly with a yield of 8.35cm and 5.53 compared to controls of only 4.5cm and 4 pieces. It is hoped that for future research, the next researcher will be able to carry out further tests to find out the inhibitors in sheep dung so that the production costs can be even cheaper than using synthetic tryptophan.