Microbial and physicochemical properties of sugarcane bagasse for potential conversion to value-added products

Authors: Wright, Maureen; Lima, Isabel; Bigner, Renee

Submitted to: International Sugar Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2015
Publication Date: 6/1/2016
Citation: Wright, M.S., Lima, I.M., Bigner, R.L. 2016. Microbial and physicochemical properties of sugarcane bagasse for potential conversion to value-added products. International Sugar Journal. 118:424-433.

Interpretive Summary: Sugarcane factories amass literal mountains of bagasse, the solid remains of the process of crushing sugarcane stalks to collect juice. Some is burned, producing energy on-site to operate the factory. As factories become more energy efficient the amount of unburned bagasse increases. Transporting a sufficient volume of bagasse in its natural state for use as fuel off-site is neither practical nor cost-effective. There is potential to convert the material to a more transportable form such as pellets. The fibers, residual sugars, and other chemicals in bagasse are a potential source for endproducts other than fuel, such as feed or mulch. This study addresses what chemicals and microbes are present in bagasse from a laboratory farm and multiple factories. The data presented here indicate the levels of sugars for potential use as feed, the levels of microbes that can potentially destabilize beneficial components, and that covering a bagasse pile stabilizes the fuel value.

Technical Abstract: Sugarcane bagasse is a potential source for commercially-viable products such as animal feed, mulch, or fuel. The applications will be determined by the levels of moisture, ash and beneficial chemicals in the bagasse. Manufacturing value-added products will be impacted by microbes, and may require microbial conversion of the substrate. Microbes present in bagasse have the potential to interfere with the production of desired products. An initial analysis of both microbes and chemicals present in bagasse is necessary to determine the most viable potential applications. This study evaluates the microbial and physico-chemical properties in sugarcane bagasse samples from three different varieties in a research setting, and samples of mixed bagasse varieties at three factories. All samples were collected in south Louisiana. Stalks from individual varieties were either shredded or passed through a roller mill. The fresh mixed variety bagasse was collected from the final tandem mill at a factory. The stored mixed variety bagasse was collected from piles at the factories. Microbial counts and types were compared across varieties and processing methods, and were correlated with physicochemical analyses. Fuel value of bagasse was significantly reduced when the bagasse was stored uncovered.