Sweet sorghum complementing ethanol production in sugar mills

Participants at the meeting. Photo: PS Rao, ICRISAT

To help the government achieve the national ethanol blending targets of 20% by 2017, private sugar mills and the public sector research institutes are collaborating with ICRISAT to identify and test sweet sorghum varieties suitable for ethanol production. A total of seven sugar mills are associated with ICRISAT in this 3-year project.

At the first Annual Review cum Work Planning meeting many sweet sorghum hybrids were identified as suitable for ethanol production.

As part of the project the agronomy for achieving higher yields is being perfected. Participants compared the economics of ethanol production from both sugarcane and sweet sorghum and highlighted the advantage of sweet sorghum over sugarcane. They all expressed interest in strengthening the collaboration and offered land for trials and usage of their distilleries for quantifying ethanol production.

Achievements for Year 1:

• A big mill test was successfully conducted at Madhucon Sugars, Telangana without changing any of the mill settings. The test showed a primary brix (sugar content of a solution) of 15^o which is close to sugar cane.
• Bagasse utilization is critical in sweet sorghum value chain and one of the possible uses of bagasse is through composting. Among the ten microbial strains studied for their efficiency in composting, three strains (Myceliophtora thermophila ATCC-48104, Aspergillus awamori and Bacillus subtilis) were found to enhance bagasse composting, with more than 65% of the bagasse getting degraded within 60 days in rice straw as well as farm yard manure amended treatments. Microbial treatments enhanced micronutrient contents of the composted bagasse.
• The results from planting dates experiments indicated that brix content of sweet sorghum at harvest was influenced by dates of sowing, the stem girth varied with the cultivar, while plant height was affected by both dates of sowing and cultivar. The fermentation efficiency was high (>90%) for juice from two genotypes ICSV-93046 and ICSV-25306 varieties.
• More than 100 sugar mill staff and sweet sorghum farmers trained in the project for achieving higher yields in sweet sorghum.

Work plans for Year 2

• In the multilocation trials a new trial will be formulated by adding 4 new entries making a total of 11 entries. ICRISAT and Indian Institute of Millets Research (IIMR) to contribute the entries and the trial guidelines along with seed material.
• Big mill test will be conducted at Ganesh Sugars in 2016 rainy season with IIMR and ICRISAT supplying the seed.
• Ratooning experiment and date of sowing experiment will be conducted in 2016
• Juice quality assessments of selected sweet sorghum genotypes and establishing their fermentation efficiencies; assessing the water requirement per unit of ethanol and effluent analysis
• The effect of microbes on sweet sorghum bagasse will be validated and the compost produced in year 1 will be tested in glass house and field
• Capacity building programs will be conducted (1 in each target state)

The meeting was held at ICRISAT on 30 May and attended by 31 scientists and managers including Dr Vilas A Tonapi, Director, IIMR, Mr JP Singh, Chief Cane Advisor, National Federation of Cooperative Sugar Factories, participants from Jawaharlal Nehru Technological University, Hyderabad, private sugar mills and ICRISAT.