Inspiration

India is still primarily an agrarian economy, with the sector contributing to almost 15.4 percent of the net Gross Domestic Product The World Factbook: India, 2018 and around 58.6 percent of the population is engaged in some form of agricultural activity. Agriculture is therefore, not only a means of income for a majority of the Indian population, but also a form of cultural identity for farmers across the nation. The fourteenth-century philosopher Ghagh also goes on to declare, rather whimsically, in one of his poems that “Heaven would be found in a farm close to a village [...]”. With agriculture forming such an important part of the cultural and emotional fabric of the country, it was only natural for us to choose a problem that greatly affected the livelihoods of farmers in the country.

Figure 1: A farm in Kerala, India

A majority of our team members belong to the Indian states of Karnataka, Maharashtra, Tamil Nadu or Uttar Pradesh — states with the most arable land and states which are major producers of sugarcane (Saccharum officinarum). Sugarcane is not only the primary input in the production of sugar, but it is also an important input in many other industries such as ethanol production and power generation (See Figure 2). The sugar industry is also one of the largest employers of the rural Indian population, providing around 500,000 jobs and impacting the lives of almost 50 million farmers. Evidently, sugarcane is also one of the most widely-grown cash-crop in the country — cultivated on around 50 million hectares of land.

We therefore chose to work on a problem plaguing both sugarcane farmers and the sugar industry: the problem of post-harvest sucrose deterioration.

Figure 2: Uses of sugarcane in the sugar and allied industries

The Problem

Sugarcane is a perennial species of grass that is cultivated primarily for its high sucrose content. The plant contains an enzyme called invertase that cleaves sucrose to provide cells with fuel for the processes of respiration and energy and carbon source for the synthesis of chemical compounds. This enzyme plays an important role in sucrose metabolism and regulation Ansari, M. I., et al., 2013. In live cane, the sucrose, therefore, is present under a dynamic balance between its synthesis and utilisation. Once the cane is harvested, this equilibrium breaks down. Instead of maintaining the levels of sucrose, the cells — under stress due to the harvest — hastily break down the sucrose, using invertase, into its components: fructose and glucose. To put this into perspective, harvested cane undergoes a reduction in weight by almost 7.4 to 17.0 percent and a reduction in the amount of sucrose by anywhere between 2 to 10 percent. These losses drastically affect both the farmer and the sugar mills.

(Graphic here to show the action of invertase?)

The retrieval rate of sugar from sugarcane is just 10.25% and this is remarkably low for a country heavily dependent on agriculture, such as India. The income, and therefore the livelihoods, of sugarcane farmers are dependent on the quality of cane they grow, making them the victims of this problem. We therefore wanted to come up with a solution that effectuated grassroot-level changes for farmers like Swaminathan.

Current Practices

This problem of post-harvest sucrose deterioration is widely known in the sugar industry Saxena et al., 2010 but there have been no satisfactory solutions till date. The primary solution used currently to mitigate these losses is to reduce the time taken to transport the cane from the farm to the mill; however India faces acute land shortages which makes it difficult to place mills within reasonable distances of the farm. Moreover, most farmers in India still harvest their crop manually which increases the time period between transport and sugar extraction.

Although mechanisation is a possible alternative, it exacerbates the problem when applied in unsuitable conditions Ghasemnejad and Jamshidi, 2011 and often results in quality deterioration Singh and Solomon, 2003. Singh and Solomon 2003 also reported that mechanised harvesting and chopping of canes resulted in a quicker deterioration if the time between the harvest and crushing is delayed by more than 24 hours.

Our Solution

We propose to target the invertase enzyme responsible for this post-harvest loss by “neutralising” it with an anti-invertase enzyme produced by genetically-engineered Escherichia coli. The farmer would introduce our genetically-modified E. coli into the stem of the sugarcane by means of a polymer-based inoculant which would be injected into the sugarcane matrix. Once inside, the genetic circuit inside the bacterial chassis is designed to exhibit anti-invertase activity regulated by the amount of fructose and glucose inside the sugarcane in a continuous and controlled manner.

Since our bacteria is closely involved with a consumable product (that you probably ingested before/while reading this wiki) we kept in mind the significance of biosafety and designed a robust three-tier failsafe mechanism. At every stage we have tried our best to consult with various stakeholders and subsequently revised our project design to bring it one step closer to being deployable in the market.

(Graphic of E. coli showing how the system works?)

The COVID-19 pandemic has caused widespread economic damage to all sectors of the economy, including the sugar industry. Mills have been non-operational for a significant amount of time due to prevailing restrictions and even when these measures are relaxed, it would take time for the fills to reach their complete capacity. Sugarcane that was already harvested is being stored for long times without any form of preprocessing, exacerbating the problem. This adds even greater relevance to our product.

Furthermore, sugarcane is also a major crop in countries such as Brazil, Mauritius, Mexico, Cuba and Indonesia. These countries too have been facing problems with post-harvest deterioration. We believe that our product can also be expanded for use in these areas of cultivation.

SugarGain is our way of making the world a sweeter place (quite literally!).

(Project Logo)

References

1. The World Factbook: India. CIA World Factbook.

   (n.d.). Retrieved on August 09, 2020. from https://www.cia.gov/library/publications/the-world-factbook/geos/in.html

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2. Ansari, M. I., Yadav, A., & Lal, R. (2013).

   An-Overview on invertase in sugarcane.

   Bioinformation 9(9), 464-465.

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3. Saxena, P., Srivastava, R. & Sharma, M. (2010).

   Impact of cut to crush delay and bio-chemical changes in sugarcane.

   Australian Journal of Crop Science. 4, 692-699.

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4. Ghasemnejad, M.H. & Jamshidi, A. (2011).

   Forecast model of sugar loss due to mechanical harvesting of the sugarcane crop.

   Australian Journal of Basic Applied Sciences. 5(12), 1190-1194.

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5. Singh, I., & Solomon, S. (2003).

   Post-harvest quality loss of sugarcane genotypes under sub-tropical climate : Deterioration of whole stalk and billets.

   Sugar Tech 5(4), 285-288.

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