Microbiology in the sugar industries

Authors: Wright, Maureen

Submitted to: Zuckerindustrie
Publication Type: Proceedings
Publication Acceptance Date: 1/4/2018
Publication Date: 1/1/2018
Citation: Wright, M. 2018. Microbiology in the sugar industries. Sugar Industry. 143(2):83-87.

Interpretive Summary: Microbes impact processing in both sugarcane, sweet sorghum and sugar beet factories. A cost-effective method to detect mannitol was developed for sugarcane as an indicator of the presence of microbes in sugar processing samples. The method was later extended for use with sweet sorghum and sugar beets. Additionally, HPLC detection of mannitol can be used in factories. The detection specificity is higher, but the cost of the equipment may not warrant the investment. Microbes can also impact the potential to use the solid plant material, bagasse, which remains after juice is removed from the stalks. Some bagasse is spread back on the fields to enhance growth of subsequent crops, but more is generated than can be used in this way. Converting bagasse for other uses will require stabilizing of the material for processing after the harvest season has ended. Microbial and physicochemical properties of bagasse from sugarcane and sweet sorghum indicated that covering sugarcane bagasse contributed to stabilizing the fuel value of the material. Pelletizing of sweet sorghum bagasse confirmed that beneficial chemical properties were maintained in a more easily transported form.

Technical Abstract: The environment of a sugar factory is conducive to the propagation of microbes that are introduced with the harvested crop. Further introductions are made from the machinery surfaces and water during processing. Each microbe type has a preferred range of temperature and moisture, so a factory may have different populations in different areas. It is important to detect microbial presence so appropriate control measures can be taken, and to conserve expenses when treatment is not needed. The most ideal detection methods in a factory will yield accurate results quickly and inexpensively. A mannitol detection method has been developed for the sugarcane industry, and subsequently applied to sweet sorghum and sugar beet. Conversion of sugar crop byproducts, such as bagasse, are a potential new value stream. An analysis was conducted to determine whether environmental conditions and the presence of microbes in bagasse affects the chemical composition, and subsequent application for novel uses. Fuel value was found to be negatively affected when bagasse was left uncovered and exposed to sun and rain. The fuel characteristics were maintained. Bagasse was also successfully pelletized and converted to biochar for stable storage and transport.