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Weissella paramesenteroides has potential as an industrial biocatalyst due to its ability to produce lactic acid. A novel strain of W. paramesenteroides was isolated from ensiled sorghum. The genome was sequenced using a hybrid assembly of Oxford Nanopore and Illumina data to produce a 2-Mbp genome and 22-kbp plasmid sequence.

Changes in chemical composition of warm-season perennial grasses during the growing season affect conversion of biomass to biofuels, thus influencing choice of harvest date. The objective was to quantify these changes for three candidate bioenergy grasses in the USA Gulf Coast region during two growing seasons and relate them to optimal harvest management. Grasses included two elephantgrass [Pennisetum purpureum Schum.; synonym Cenchrus purpureus (Schumach.) Morrone] entries, ‘Merkeron’ and breeding line UF1, and the energycane (Saccharum spp. hybrid) cultivar ‘L79-1002’. Quantification of cell wall constituents and mineral composition of above-ground biomass occurred monthly throughout the growing season. With the exception of hemicellulose, elephantgrass cell wall constituents (cellulose, lignin, neutral detergent fiber and acid detergent fiber) increased from early in the growing season until late summer and either remained relatively constant (UF1) or increased slightly (Merkeron) during the remainder of the season. In contrast, concentrations of energycane cell wall constituents peaked in late summer and decreased during the remainder of the growing season. Nitrogen, P, and ash concentrations decreased with increasing maturity for all grass entries, and they were much greater in leaf than in stem. Elephantgrass leaf, particularly of UF1, contributed less to total biomass harvested than energycane leaf. Likewise, the proportion of total ash harvested that was in the leaf fraction was greater for energycane than for elephantgrass when harvest occurred late in the growing season. Thus, delayed harvest until late in the season was generally a superior management strategy for elephantgass because it resulted in biomass with greater cell wall constituent concentrations, lesser leaf percentage, and lesser concentrations of N and ash, all of which may provide advantages in some conversion processes. In contrast, greater accumulation of extractives by energycane and greater lignin concentration in elephantgrasses late in the growing season may reduce efficiency of some conversion methods.

Sweet sorghum [Sorghum bicolor (L.) Moench] is a promising crop for bioenergy production but is susceptible to lodging, which has the potential to significantly affect biomass composition and total harvestable yield. Despite known susceptibility to lodging, there are limited data available on the effects of root lodging on biomass and carbohydrate yield and partitioning in lodged sweet sorghum. Therefore, weather-induced lodging of field-grown sweet sorghum in 2012 and 2013 in North Central Florida was exploited to provide a better understanding of the effects of root lodging on biomass and carbohydrate yield and partitioning to leaf, stem, and panicle. Fresh biomass yields were not different between lodged and non-lodged plots in 2012 or 2013, but dry biomass yield was lower during 2012. Grain yield was lower during both years of the study, as a result of lodging. However, no difference in leaf or stem biomass yield was seen due to lodging. Lodging reduced biomass recovered by flail harvester at harvest by 40% during 2012. Juice Brix showed a 32 and 17% decline in lodged compared to non-lodged sorghum at harvest during 2012 and 2013, respectively. Total nonstructural carbohydrates (starch and water soluble carbohydrates) showed a 27% reduction on a whole plant basis as a result of lodging during 2013, with panicles showing a greater percent reduction (53 vs. 18%) in total nonstructural carbohydrates (mostly starch) as a result of lodging compared with stems (mostly water soluble carbohydrates). Although sweet sorghum is susceptible to root lodging in many environments, it is likely to have only a relatively modest effect on water-soluble carbohydrates in the stem.

Carbohydrate and lignin composition of feedstock materials are major factors in determining their bioenergy potential. This study was conducted to quantify dry biomass yield and the carbohydrate and lignin composition of six potential biofuel grasses (elephantgrass, energycane, sweetcane, giant reed, giant miscanthus, and sugarcane) across three sites in Florida for plant (2009) and first ratoon (2010) crops. Dry biomass yields ranged from about 30 to 50 Mg ha−1 and were generally greatest for elephantgrass, energycane, sweetcane, and sugarcane. Accordingly, total plant carbohydrate yields (20 to 25 Mg ha−1) were comparable among sugarcane, energycane, sweetcane, and elephantgrass, but were generally less for giant reed and even less for giant miscanthus. However, the contribution of total extractable carbohydrates and total fiber carbohydrates to total plant carbohydrate yields differed among species. Sugarcane had the highest concentrations of extractable carbohydrates (219 to 356 mg g−1), followed by energycane, then sweetcane, elephantgrass, and giant reed, with giant miscanthus having the lowest. Energycane and elephantgrass tended to have significantly more fiber glucose, and elephantgrass less xylose, than other species. Variability in total lignin concentrations on a fiber basis was relatively modest (250 to 285 mg g−1) across species, but was generally highest in sweetcane and giant reed. Overall, elephantgrass and energycane were prime regional candidates for cellulosic conversion using fermentation processes due to high yields and favorable fiber characteristics, although energycane tended to have higher extractable carbohydrates.

Biomass yield and tissue mineral composition can affect total energy yield potential, conversion efficiencies and environmental impacts, but relatively few data are available for sweet sorghum [Sorghum bicolor (L.) Moench] grown in the southeastern USA. Therefore, a study was conducted at two locations in North and Central Florida on marginal sand soils comparing the effects of planting date (PD) on dry biomass yield and mineral composition of leaf, stem, and grain heads for ‘M-81E’ and ‘Dale’ sweet sorghum cultivars. Overall tissue mineral concentrations were relatively low for sweet sorghum, attributable to low K and Ca concentrations. Ash and mineral concentrations were generally greater for Dale, especially for the early PD. Leaf and grain heads were greater in mineral concentrations compared to stems. Dry biomass yield averaged 19.4 Mg ha−1 and was greater for M-81E and the early PD. Stems accounted for 73% of the total biomass compared to leaves (13%) across all treatments. Total N, P, and K removals averaged 136, 27.6, and 81.4 kg ha−1, respectively. Overall, leaves removed 30, 23, and 19% of total N, P, and K compared to 34, 34, and 61% by stem, respectively. Considering lower biomass but greater mineral concentrations in leaf and grain heads compared to stems, returning leaf residues and possibly grain heads to the soil have the potential to offset nutrient and energy inputs needed on these marginal soils and enhance the sustainability of sweet sorghum cropping systems.

To test the suitability of DNA stable isotope probing (DNA-SIP) for characterizing bacterial spore populations in soils, the properties of Bacillus subtilis cells and spores intensely labeled with [(13)C]glucose were characterized. Spore germination, vegetative growth rates, and sporulation efficiency were indistinguishable on glucose versus [(13)C]glucose, as were spore wet heat and UV resistance. Unlabeled and (13)C-labeled spores contained 1.0989 and 74.336 at.% (13)C, and exhibited wet densities of 1.356 and 1.365 g/ml, respectively. Chromosomal DNAs containing (12)C versus (13)C were readily separated by their different buoyant densities in cesium chloride/ethidium bromide gradients.

The agronomic performance, cell wall characteristics and enzymatic saccharification efficiency of transgenic sugarcane plants with modified lignin were evaluated under replicated field conditions. Caffeic acid O-methyltransferase (COMT) was stably suppressed by RNAi in the field, resulting in transcript reduction of 80%-91%. Along with COMT suppression, total lignin content was reduced by 6%-12% in different transgenic lines. Suppression of COMT also altered lignin composition by reducing syringyl units and p-coumarate incorporation into lignin. Reduction in total lignin by 6% improved saccharification efficiency by 19%-23% with no significant difference in biomass yield, plant height, stalk diameter, tiller number, total structural carbohydrates or brix value when compared with nontransgenic tissue culture-derived or transgenic control plants. Lignin reduction of 8%-12% compromised biomass yield, but increased saccharification efficiency by 28%-32% compared with control plants. Biomass from transgenic sugarcane lines that have 6%-12% less lignin requires approximately one-third of the hydrolysis time or 3- to 4-fold less enzyme to release an equal or greater amount of fermentable sugar than nontransgenic plants. Reducing the recalcitrance of lignocellulosic biomass to saccharification by modifying lignin biosynthesis is expected to greatly benefit the economic competitiveness of sugarcane as a biofuel feedstock.

Growth of Bacillus subtilis cells, normally adapted at Earth-normal atmospheric pressure (∼101.3 kPa), was progressively inhibited by lowering of pressure in liquid LB medium until growth essentially ceased at 2.5 kPa. Growth inhibition was immediately reversible upon return to 101.3 kPa, albeit at a slower rate. A population of B. subtilis cells was cultivated at the near-inhibitory pressure of 5 kPa for 1,000 generations, where a stepwise increase in growth was observed, as measured by the turbidity of 24-h cultures. An isolate from the 1,000-generation population was obtained that showed an increase in fitness at 5 kPa when compared to the ancestral strain or a strain obtained from a parallel population that evolved for 1,000 generations at 101.3 kPa. The results from this preliminary study have implications for understanding the ability of terrestrial microbes to grow in low-pressure environments such as Mars.