Jatropha curcas, L. Pruning Residues for Energy: Characteristics of an Untapped By-Product

Heterologous Expression of Jatropha curcas Fatty Acyl-ACP Thioesterase A (JcFATA) and B (JcFATB) Affects Fatty Acid Accumulation and Promotes Plant Growth and Development in Arabidopsis

Plant fatty acyl-acyl carrier protein (ACP) thioesterases terminate the process of de novo fatty acid biosynthesis in plastids by hydrolyzing the acyl-ACP intermediates, and determine the chain length and levels of free fatty acids. They are of interest due to their roles in fatty acid synthesis and their potential to modify plant seed oils through biotechnology. Fatty acyl-ACP thioesterases (FAT) are divided into two families, i.e., FATA and FATB, according to their amino acid sequence and substrate specificity. The high oil content in Jatropha curcas L. seed has attracted global attention due to its potential for the production of biodiesel. However, the detailed effects of JcFATA and JcFATB on fatty acid biosynthesis and plant growth and development are still unclear. In this study, we found that JcFATB transcripts were detected in all tissues and organs examined, with especially high accumulation in the roots, leaves, flowers, and some stages of developing seeds, and JcFATA showed a very similar expression pattern. Subcellular localization of the JcFATA-GFP and JcFATB-GFP fusion protein in Arabidopsis leaf protoplasts showed that both JcFATA and JcFATB localized in chloroplasts. Heterologous expression of JcFATA and JcFATB in Arabidopsis thaliana individually generated transgenic plants with longer roots, stems and siliques, larger rosette leaves, and bigger seeds compared with those of the wild type, indicating the overall promotion effects of JcFATA and JcFATB on plant growth and development while JcFATB had a larger impact. Compositional analysis of seed oil revealed that all fatty acids except 22:0 were significantly increased in the mature seeds of JcFATA-transgenic Arabidopsis lines, especially unsaturated fatty acids, such as the predominant fatty acids of seed oil, 18:1, 18:2, and 18:3. In the mature seeds of the JcFATB-transgenic Arabidopsis lines, most fatty acids were increased compared with those in wild type too, especially saturated fatty acids, such as 16:0, 18:0, 20:0, and 22:0. Our results demonstrated the promotion effect of JcFATA and JcFATB on plant growth and development, and their possible utilization to modify the seed oil composition and content in higher plants.

Pruning harvesting with modular towed chipper: Little effect of the machine setting and configuration on performance despite strong impact on wood chip quality

Pruning residues can have a high quality as feedstock for energy purposes and are largely available in Europe. However, it is still an untapped resource. Such scarce use is due to the need to optimize their supply chain in term of collection machines and the associate cost of collection. A modular chipper (prototype PC50) for pruning harvest was developed. Such prototype is adaptable to various harvesting logistics and may produce a higher quality woodchip compared with the one produced by shredders available in the market. In this work, we tested the performance and quality of the product delivered by the prototype PC50 in various conditions and plant species, after a modulation of the machine settings (counter-rotating toothed rollers [CRR] speed), loading systems ([LS], either big bag or container), and knife types ([KT], either discontinuous hoe shaped knives or continuous helicoidal knives). To take into account of the covariates in the experiment (Cropping season and plant species), LSmeans were computed to have an unbiased estimate of the treatments means. The modulation of LS and KT scarcely affected the performance of the machine. In particular, the choice of the KT affected the field efficiency when the LS was a Tilting box but not a Big Bag. Whereas the continuous knife resulted in a 97% higher material capacity compared to hoe shape knives, the last of which the amount of short sized (<16 mm) fractions compared to helicoidal knives. No role of the CCR was found on the machine performance, but increasing CRR speed reduced the chip apparent bulk density and the fraction chips with a size <8 mm.

The Influence of the Use of Windrowers in Baler Machinery on the Energy Balance during Pruned Biomass Harvesting in the Apple Orchard

The effective operation of machinery in agricultural processes is crucial in terms of energy efficiency, economic consequences, and environmental footprint. The agricultural sector provides many opportunities to bring biomass to the market. An interesting option is to collect the branches after a regular pruning of apple orchards in the winter-spring season. As the harvesting of pruning residues in apple orchards for energy purposes demands additional primary energy, any measures that increase the amount of collected biomass are desirable. In this study, the influence of pruning harvesting using a baler with and without windrowers on pruning biomass yield, energy input and output flow, energy balance, CO2 emission reduction, and costs of that operation in apple orchards was investigated. The performed analysis, based on the results from two apple orchards, revealed that the energy balance was positive for both variants. However, in comparison with the harvesting process without windrowers, the use of windrowers in these two orchards caused an increase in pruning biomass yield by 0.45 tDM·ha−1 per year (25%) and 0.54 tDM·ha−1 per year (33%), respectively. The energy balance increased up by ca. 0.8–1.0 GJ·ha−1, although the fuel consumption by the tractor was higher. The use of windrowers did not significantly increase the costs, but resulted in remarkably better income from biomass selling (ca. €30–40 ha−1). Finally, the increase in the mass of harvested biomass led to a higher potential CO2 emission reduction. As a result, pruning biomass is an attractive source of energy, especially for local markets.