Identification of Microbial Populations in Blends of Worm Castings or Sugarcane Filter Mud Compost with Biochar

Soil amendments are used to improve soil quality, thereby enhancing plant growth and health. Efforts have been made to replace synthetic chemical enhancers. It is also preferable to not use natural products such as peat moss, the harvesting of which can be harmful to marine ecosystems. Viable replacements include worm castings, which can contribute beneficial microbes, as well as physicochemical amendments. Another potential soil amendment is the compost produced from sugarcane processing byproducts. While the texture of these two materials is not ideal for even dispersal onto fields, the addition of biochar improves the texture. Previous work demonstrated that blending them with biochar from sugarcane byproducts added physicochemical benefits, while not quantitatively reducing the microbial load, even after storage. Microbial populations of the blends in the present study were found to (1) contain taxonomic groups that contribute to plant health and (2) not contain human pathogens. Based on the quantitative and qualitative microbial analyses, it has been determined that 50% or less biochar in a blend will allow maintenance of beneficial microbes in stored samples.

Molecular and Toxicity Analyses of White Granulated Sugar and Other Processing Products Derived From Transgenic Sugarcane

This study aimed to prepare the sugar industry for the possible introduction of genetically modified (GM) sugarcane and derived retail sugar products and to address several potential public concerns regarding the characteristics and safety of these products. GM sugarcane lines with integrated Cry1Ab and EPSPS foreign genes were used for GM sugar production. Traditional PCR, real-time fluorescent quantitative PCR (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) were performed in analyzing leaves, stems, and other derived materials during sugar production, such as fibers, clarified juices, filter mud, syrups, molasses, and final GM sugar product. The toxicity of GM sugar was examined with a feeding bioassay using Helicoverpa armigera larvae. PCR and RT-qPCR results showed that the leaves, stems, fibers, juices, syrups, filter mud, molasses, and white granulated sugar from GM sugarcane can be distinguished from those derived from non-GM sugarcane. The RT-qPCR detection method using short amplified product primers was more accurate than the traditional PCR method. Molecular analysis results indicated that trace amounts of DNA residues remain in GM sugar, and thus it can be accurately characterized using molecular analysis methods. ELISA results showed that only the leaves, stems, fibers, and juices sampled from the GM sugarcane differed from those derived from the non-GM sugarcane, indicating that filter mud, syrup, molasses, and white sugar did not contain detectable Cry1Ab and EPSPS proteins. Toxicity analysis showed that the GM sugar was not toxic to the H. armigera larvae. The final results showed that the GM sugar had no active proteins despite containing trace amounts of DNA residues. This finding will help to pave the way for the commercialization of GM sugarcane and production of GM sugar.

Abundance and diversity of soil macroinvertebrates in sugarcane (Saccharum spp.) plantations under organic and chemical fertilization in Belize

Many studies suggest that sugarcane management practices have negative impact on soil quality, especially on soil organisms, however, information on macroinvertebrate abundance and diversity in conventional sugarcane fields is scarce. This study determined the abundance and diversity of soil macroinvertebrates in sugarcane plantations under 2 types of soils, Cambisol and Fluvisol, with three types of fertilizer management: chemical fertilizer, vinasse and filter mud, and in a secondary forest (on a Cambisol). Sampling was carried out in northern Belize during two crop cycles (from May 2013 to May 2015). Soil macroinvertebrates were collected using monoliths based on Tropical Soil Biology and Fertility (TSBF) Handbook of Methods at the end of the rainy seasons. The parameters evaluated were biomass, density and diversity of soil macroinvertebrates (number of morphospecies, an ecological index for tropical soil quality based on macrofauna, and a converted Shannon index (H_exp)), yield and plant response variables (number of stool, number of stem, number of active leaves, stem length and stem diameter). A total of 7,634 individuals were identified, grouped into 52 morphospecies belonging to 16 orders and three species of annelids. No significant differences existed among management systems (application of chemical fertilizer, vinasse, filter mud and secondary forest) on abundance and diversity of soil macroinvertebrates, yield and plant variables. However, there were significant differences between soils and cycles in some evaluated parameters. Presuming that soil type and seasonal conditions, in a two years trial, had higher weight on determine the studied parameters than the different management systems.

Effective Removal of Lead from Solution by Sulfate Reducing Bacteria Cultured with Sugar Byproducts

Sulfate reducing bacteria (SRB) are widely used to remove heavy metals because of their high efficiency. However, the metabolic processes of SRB require additional carbon sources, and the development of low-cost carbon sources has gradually attracted attention. The utilization of sugar byproduct resources, as the low-cost carbon sources, has great practical significance for environmentally sustainable development in Guangxi, China. This study aims to cultivate SRB with low-cost sugar byproducts, apply them to controlling a lead-polluted environment, and study the effects and mechanisms of controlling lead pollution. The research results show that the best culture effect of SBR can be obtained by mixing the filter mud and vinasse in a ratio of 1:1 to 3:1. SRB have average lead removal rates of more than 96.97% in solutions with different lead concentration of 10∼100 mg/L, and SRB have a higher tolerance to high concentrations of lead due to factors such as the organic substance composition of sugar byproducts and the porosity of filter mud. Scanning electron microscopy combined with energy dispersive spectrometry and X-ray diffraction analysis show that SRB mainly cause Pb2+ to form PbS precipitate through redox reactions to remove lead from the solution. Therefore, low-cost filters of a mud and vinasse mixture can be used as a medium for SRB and exhibit high heavy metal removal efficiency, thus providing a new utilization of filter mud and vinasse.