Biomass Harvesting Research Articles

Physiological and biochemical characterization of new wild strains of Kappaphycus alvarezii (Gigartinales, Rhodophyta) cultivated under land-based hatchery conditions

The red alga Kappaphycus alvarezii is globally cultivated as a major source of k-carrageenan. Farming of this species through clonal propagation has been confined to a few good-quality commercial strains. After more than 50 years of successful cultivation and high productivity, the production of K. alvarezii in most “cottonii”-producing countries like the Philippines had declined in recent decades. This can be attributed to low genetic variability, making “old” cultivars more susceptible to environmental stressors, pests (epi- and endophytes) and diseases (e.g., ice-ice). Hence, the establishment of new cultivars from wild strains with desirable traits may provide alternative seedstocks with different genetic makeup from the currently farmed cultivars. Here, we examined the physiological and biochemical properties of 10 new wild strains of K. alvarezii, belonging to four non-commercially cultivated haplotypes, collected from Eastern Samar, Philippines. These strains were cultivated in an outdoor, land-based hatchery with ambient light and flow-through, nutrient replete seawater. Growth rates, ranging from 0.44 % to 3.74 % d-1, significantly varied among the strains but did not significantly vary among haplotypes. The cultivars also showed a notable change in color and morphology as they adapted to hatchery conditions. Pigments and total phenolic content did not significantly vary among cultivars. Proximate analysis showed that the dry biomass of all K. alvarezii strains was composed mainly of ash (ranging from 39.2 % to 51.0 %), followed by carbohydrate (ranging from 26.0 % to 35.3 %), and with trace amounts of proteins (ranging from 1.02 % to 4.61 %). Moreover, tissue stoichiometry (C, N and P) was comparable among the 10 strains. Considering the promising growth performance of strain SamW-014 under hatchery condition, we recommend its cultivation at sea and conduct corresponding carrageenan yield and quality analyses on its raw dried biomass. Among the 10 strains, five others are also of interest and for consideration. Thereafter, selected strain(s) will be introduced to seaweed farmers for future cultivation to increase biomass production, harvest yields, and income.

Cultivation of Chlorella sorokiniana IPPAS C-1 in Flat-Panel Photobioreactors: From a Laboratory to a Pilot Scale.

Flat-panel photobioreactors are effective systems for microalgae cultivation. This paper presents the growth characteristics of the microalgae Chlorella sorokiniana IPPAS C-1 as a result of three-stage scale-up cultivation in a specially designed cultivation system. First, C. sorokiniana was grown aseptically in 250 mL glass vessels; then, it was diluted and inoculated into a 5-liter flat-panel horizontal photobioreactor; and, at the last stage, the culture was diluted and inoculated into a 70-liter flat-panel vertical photobioreactor. In the presented cycle, the cultured biomass increased by 326 times in 13 days (from 0.6 to 195.6 g dw), with a final biomass concentration of 2.8 g dw L−1. The modes of semi-continuous cultivation were considered. The biomass harvest and dilution of the suspension were carried out either every day or every 3–4 days. For C. sorokiniana IPPAS C-1, a conversion coefficient of optical density values to dry biomass (g L−1) was refined through a factor of 0.33. The key parameters of the photobioreactors tested in this work are discussed.

Pasture Management to Reduce the Risk of Acer pseudoplatanus Poisoning While Preserving Ecological Sustainability

In spring, grazing equids may suffer from a severe rhabdomyolysis syndrome named atypical myopathy. This environmental intoxication results from ingestion of toxins contained in Acer pseudoplatanus seedlings. The aim of this study was to investigate the effectiveness of herbicide spraying and mowing to reduce the toxic pressure of sycamore seedlings. In a first experiment, the efficacy of three herbicides to eradicate seedlings was compared to mowing. In a second experiment, the influence of the mowing timing on pasture productivity was determined. In both experiments, sycamore seedling counting, grass height and botanical composition were determined. In experiment 2, the final harvest biomass and its nutritional value were also determined. Herbicides and mowing both reduced the number of seedlings, which nevertheless disappear naturally over time without intervention (i.e., in control areas). As opposed to mowing, herbicide spraying altered the composition of the pasture flora. Both sprayed and mowed seedlings remain toxic until full decomposition. Early mowing (i.e., early April) did not affect the harvest yield. Late mowing (i.e., end of April) reduced the harvest yield but its nutritional value fitted the horses’ need. In conclusion, mowing is the best strategy to reduce the risk of Acer pseudoplatanus poisoning in grazing equids while preserving ecological sustainability and nutritional value of pastures.

Response of soil and vegetation in a warm-temperate Pine forest to intensive biomass harvests, phosphorus fertilisation, and wood ash application

The objective of this study was to assess the effects of different intensities of biomass harvesting, and the possible effects of compensation methods, on forest functioning. To do so, we carried out a split-plot experiment (SW France) crossing four different intensities of biomass harvesting (Stem-Only Harvest [SOH], Aboveground Additional Harvest [AAH], Belowground Additional Harvest [BAH], and Whole-Tree Harvest [WTH]) and three compensation methods (control [C], wood ash application [A] and phosphorus fertilisation [P]). The experimental treatments were followed by the plantation of pines (Pinus pinaster). The environmental consequences of treatments on soil and vegetation were evaluated 11 years after the tree plantation.Despite their low additional biomass exports (+10 % for AAH to +34 % for WTH), the non-conventional harvest practices exported much higher quantities of nutrients than the conventional SOH technique (+145 % of exported N in WTH). Additional biomass harvests impacted the soil organic matter content, with negative effects on P-organic, soil cation exchange capacity, exchangeable Ca, and most extractible nutrients. However, tree nutritional status was improved by P-fertiliser or wood ash. We observed a positive effect of wood ash application on soil pH and nutrient content but, like additional harvests, wood ash application decreased the pool of soil organic carbon (~10 %).Overall, the experiment showed that exporting more forest biomass due to the additional harvesting of biomass had negative consequences on the ecosystem biogeochemistry. Additional harvests have impoverished the soil, and decreased the soil organic carbon content. Importantly, applying nutrients as fertiliser or wood ash did not compensate for all the negative impacts of biomass exports and the method of wood ash recycling in forests could even decrease the soil organic carbon.

Increasing Sugar Content in Source for Biofuel Production Using Agrochemical and Genetic Approaches at the Stages of BioMass Preharvesting and Harvesting

In order to optimize biofuel (including bioethanol) production processes, various problems need to be solved, such as increasing the sugar content of raw materials/biomass to gain a higher yield of the product. This task can be solved in several ways, with their own advantages and disadvantages, and an integrated approach, such as using a combination of ripening agents and phytohormones or application of a superabsorbent polymer with at least one sugar-enhancing agent, can be applied as well. Here, we reviewed several methods, including pre- and postharvest factors (light, temperature, partial replacement of potassium with magnesium, etc.), genetic modifications (traditional breeding, phytohormones, etc.), chemical ripening methods (Ethephon, Moddus, etc.), and some alternative methods (DMSO treatment, ionic liquids, etc.). The aim of this review was to provide a comprehensive, up-to-date summary of methods of increasing the carbohydrate level in plants/biomass for bioethanol production.

Microalgae biodiesel: A sustainable source of energy, unit operations, technological challenges, and solutions

The decline in reserves of fossil fuels has shifted the world towards renewable and sustainable alternative fuels. Microalgae, a rich source of triacylglycerol, are a potential candidate for biodiesel production. The rising industrial uses of algae led to the development of different unit operations. Unraveling the biochemistry of compounds present in algae to produce biofuels and byproducts, biomass productivity and efficient extraction of bioactive compounds remain key hurdles. This review brings into light the different cell disruption methodologies, with reduced environmental hazards caused by conventional methods. The production of lipids for biofuel like biodiesel cannot alone sustain the algae-based economy. Therefore, using lipid extracted biomass for various other purposes serves it a solution. Lipid Extracted Biomass has numerous applications, including the production of biofuels like biohydrogen and biogas, biochar, bio-composites, carbon quantum dots and bio-polythene of different densities. It can also be used as animal feed, manure to improve soil fertility and to treat wastewater. The present article discusses the state-of-the-art technologies developed for algal biomass cultivation, harvesting and drying. This comparative discussion on different algal biofuels’ unit operations will reveal associated technological challenges arising during various unit operations, from cultivation to lipid extraction and its conversion to biodiesel. This study presents a sustainable solution for extracting lipids from microalgae by utilizing its byproducts for several commercial purposes. The study concludes that modifications are required in the conventional approaches of harvesting, drying along with cultivation to improve the bioeconomic potential of algae

The Effect of Transplant Date and Plant Spacing on Biomass Production for Floral Hemp (Cannabis sativa L.)

Floral hemp cultivated for the extraction of cannabinoids is a new crop in the United States, and agronomic recommendations are scarce. The objective of this study was to understand the effects of plant spacing and transplant date on floral hemp growth and biomass production. Field trials were conducted in North Carolina in 2020 and 2021 with the floral hemp cultivar BaOx. Transplant date treatments occurred every two weeks from 11 May to 7 July (±1 d). Plant spacing treatments were 0.91, 1.22, 1.52, and 1.83 m between plants. Weekly height and width data were collected throughout the vegetative period, and dry biomass was measured at harvest. Plant width was affected by transplant date and spacing. Plant height was affected by transplant date. Earlier transplant dates resulted in taller, wider plants, while larger plant spacing resulted in wider plants. Individual plant biomass increased with earlier transplant dates and larger plant spacing. On a per-hectare basis, biomass increased with earlier transplant dates and smaller transplant spacing. An economic analysis found that returns were highest with 1.22 m spacing and decreased linearly by a rate of −163.098 USD ha−1 d−1. These findings highlight the importance of earlier transplant timing to maximize harvestable biomass.

Interaction of flow turbulence and nitrogen nutrients on the growth of Scenedesmu Quadricanda

The effects of hydrodynamics and nutrients on algae growth have received considerable attention. In this study, the research of the interaction of flow turbulence and nitrogen nutrients on the growth of Scenedesmu Quadricanda was investigated. Scenedesmu Quadricanda was cultured under different turbulence intensities and nutrients conditions. Furthermore, the improved logistic model was used to unify the effect of nutrient flux and hydraulic diffusion flux on algal growth. Algae cell integrity, chlorophyll-a concentration, and polysaccharide content were determined to represent the algal growth. Results showed that the high turbulence intensity (turbulent energy dissipation rate 3.25 × 10−3 fm2/s3–8.93 × 10−3 m2/s3) and total nitrogen (TN) concentration increased algal density and chlorophyll-a. However, there was no significant correlation between the concentration of TN and turbulence intensity and the growth rate of algae. The polysaccharide determination results showed that the increase of TN concentration would reduce extracellular polymeric substances (EPS), which would reduce the aggregation of algal cells. Moreover, high turbulence intensity promoted the production and accumulation of intracellular polysaccharides (IPS) and inhibited the secretion of EPS. The analysis of the improved logistic model verified that the increase of both TN concentration and turbulent intensity increased the production of chlorophyll-a, maximum biomass, and the intrinsic rate of increase. The findings indicate that flow turbulence and nitrogen nutrients have a synergistic effect on algal growth, chlorophyll-a content, polysaccharide secretion, and nutrient uptake, which can foster further investigations on the control of algal bloom and harvest of microalgae biomass.

Growing season carbon dynamics differ in intermediate wheatgrass monoculture versus biculture with red clover

Perennial crops can improve the ecological and economic sustainability of agroecosystems because of their potential to provide diverse ecosystem services including carbon storage. Intermediate wheatgrass (IWG; Thinopyrum intermedium) is a stress-tolerant grain and forage species that can be grown in bicultures with legumes for symbiotic nitrogen fixation that provide additional ecosystem services but also compete with IWG for resources and may diminish field-scale carbon uptake. An eddy covariance (EC) tower was installed in December 2018 in an IWG field in Wisconsin – in which half of the field was frost seeded with red clover (Trifolium pratense L.) – to investigate how perennial grain bicultures and monocultures differ in carbon accumulation compared to monocultures. Using a combination of spatially-partitioned carbon and energy fluxes, collected biomass samples, and harvest and manure estimates, we found that IWG monocultures were larger carbon sinks (–538 to –580 g C m−2 yr−1) compared to bicultures (–458 to –520 g C m−2 yr−1), due to greater photosynthetic activity during the growing season and following harvests in August each year. In contrast, evapotranspiration rates were greater in bicultures compared to monocultures (by 0.3–1.4 kg H2O m−2 day−1), specifically during summer. Grain and forage harvest resulted in carbon loss which was not recovered until 30 days post-harvest. Carbon loss was greater for bicultures (by 20 g C m−2 month−1). Net ecosystem carbon balance (NECB) estimates suggested that the IWG monoculture accumulated more carbon (306 ± 88 C m−2), whereas the biculture was on average carbon neutral (7 g ± 131 C m−2), when biomass removal and manure additions were accounted for. Our study demonstrates the complexities of quantifying carbon budgets in dynamic agricultural systems over short time scales, and the importance of assessing crop multifunctionality within a site's ecological and economic context.

Gradient electro-processing strategy for efficient conversion of harmful algal blooms to biohythane with mechanisms insight

Globally eruptive harmful algal blooms (HABs) have caused numerous negative effects on aquatic ecosystem and human health. Conversion of HABs into biohythane via dark fermentation (DF) is a promising approach to simultaneously cope with environmental and energy issues, but low HABs harvesting efficiency and biohythane productivity severely hinder its application. Here we designed a gradient electro-processing strategy for efficient HABs harvesting and disruption, which had intrinsic advantages of no secondary pollution and high economic feasibility. Firstly, low current density (0.888-4.444 mA/cm2) was supplied to HABs suspension to harvest biomass via electro-flocculation, which achieved 98.59% harvesting efficiency. A mathematic model considering coupling effects of multi-influencing factors on HABs harvesting was constructed to guide large-scale application. Then, the harvested HABs biomass was disrupted via electro-oxidation under higher current density (44.44 mA/cm2) to improve bioavailability for DF. As results, hydrogen and methane yields of 64.46 mL/ (g VS) and 171.82 mL/(g VS) were obtained under 6 min electro-oxidation, along with the highest energy yield (50.1 kJ/L) and energy conversion efficiency (44.87%). Mechanisms of HABs harvesting and disruption under gradient electro-processing were revealed, along with the conversion pathways from HABs to biohythane. Together, this work provides a promising strategy for efficient disposal of HABs with extra benefit of biohythane production.

Microalgae from food agro-industrial effluent as a renewable resource for agriculture: A life cycle approach

The present study evaluated the life cycle of microalgae biomass cultivated in effluents as a soil biostimulant and nutrient source for corn (Zea Mays L.) cultivation. Six scenarios were analyzed, where two different soil types (A and B horizons) and two different functional units were investigated (100 kg of plant and 1 ha of planted area). Environmental impacts, including carbon footprint, were evaluated, along with damage assessment. The results showed that biomass harvesting and soil complementary fertilization are the main contributors to the carbon footprint. The carbon footprint can be minimized by 76.33% if chemical coagulation is replaced by gravitational sedimentation to harvest biomass. These actions also minimized impacts in freshwater ecotoxicity (-24,13%), terrestrial ecotoxicity (-25,72%), and terrestrial acidification (-68,62%). Regarding the damage assessment, gravitational sedimentation and subsequent application in soil from A horizon was the least damaging scenario.

Designing Harvesting and Hauling Cost Models for Energy Cane Production for Biorefineries

The harvesting and hauling operations of bioenergy feedstock is an important area in biofuel production. Production costs can be minimized by maintaining optimal machinery units for these operations. The objective of this study is to design an optimal harvesting unit for bioenergy refinery and estimate harvesting and hauling costs of energy cane. A biorefinery with the annual capacity of processing twenty-five million imp. gallons of ethanol were considered. Given the efficiency of harvesting, a two-row soldier system was considered. Considering the year-round supply of energy cane to the refinery, the optimal machinery unit was designed, and the combined operation costs were derived. The average estimated ownership, repair, labor and fuel and lubricant costs of biomass harvest unit were calculated to be $0.50, $0.54, $1.78 and $1.51/mt, respectively. The costs distribution generated showed harvesting and hauling costs could range between $5.47–$9.23/mt of energy cane. The methodology and the research output will provide guidelines for investors in designing harvesting and hauling units and estimating costs for different scales of operation.

Phosphorus Stock Depletion and Soil C:N:P Stoichiometry Under Annual Crop Rotations and Grassland Management Systems Over 13 Years

Phosphorus (P) nutrition is essential to both plant yield and soil organic matter (SOM) input. However, continuous extraction of P by plants and biomass harvesting can lead to soil P stock depletion, a reduction in crop yields and ultimately a reduction in organic matter input to the soil. In this work, we analysed P, C and N stock trends in the 0-30 cm topsoil layer cultivated with permanent cropland (CC) and mowed permanent grassland (GG) for 13 years. In addition, we characterized the changes in P organic forms by using 31P-NMR. The results showed that the amount of P exported within 13 years was 10% greater in GG than in CC (295 and 268 kg ha-1, respectively). The total P stocks decreased under both the CC and GG management systems (0.30 and 0.25 Mg ha-1, respectively). This depletion was mainly observed in total Pi forms, which recorded reductions of 0.75 and 0.29 Mg ha-1 in GG and CC, respectively. The total Po stock increased by 42.6% in GG; these results were consistent with the increase in C and N stocks in GG (2.6 and 0.19 Mg ha-1, respectively) and their reduction in CC (-4.2 and -0.38 Mg ha-1, respectively). Although P depletion mainly affected the P pool presenting the highest lability (labile P), this depletion did not have a negative effect on plant yield after 13 years due to the buffering capacity of P pools presenting less lability (moderately labile P). Mowing permanent grasslands led to a change in the pool of labile P from inorganic to organic forms and an increase in soil C and N stocks. Based on the 31P-NMR technique, permanent grasslands significantly reduced α-glycerophosphate and increased myo-IHP and adenosine monophosphate more than the permanent cropland. Although there was no significant decrease in productivity, the depletion of available P should be monitored over time, especially in mown permanent grassland crops, to prevent potential nutrient stress.

One-step co-cultivation and flocculation of microalgae with filamentous fungi to valorize starch wastewater into high-value biomass

A novel method of one-step co-cultivation and harvesting of microalgae and fungi, for efficient starch wastewater treatment and high-value biomass production was developed. By combination of Aspergillus oryzae and Chlorella pyrenoidosa, nutrients in wastewater could be converted to useful microbial biomass, while the wastewater was purified. Moreover, the microalgae C. pyrenoidosa could gradually be encapsulated in fungal pellets which promoted the biomass harvesting. The free algal cells could be completely harvested by fungal pellets within 72 h. The synergistic effects between them greatly improved the removal efficiencies of main pollutants as the removal efficiency of COD, TN, and TP reached 92.08, 83.56, and 96.58 %, respectively. In addition, the final biomass concentration was higher than that of individual cultures. The protein and lipid concentration was also significantly improved and reached 1.92 and 0.99 g/L, respectively. This study provides a simple and efficient strategy for simultaneous wastewater treatment and high-value biomass production.

Optimizing the Design of a Biomass-to-Biofuel Supply Chain Network Using a Decentralized Processing Approach

When designing biomass-to-biofuel supply chains, the biomass uncertainty, seasonality and geographical dispersion that affect economic viability need to be considered. This work presents a novel methodology that can optimize the design of biofuel supply chains by adopting a decentralized network structure consisting of a mix of fixed and mobile processing facilities. The model considers a variable biomass yield profile and the mobile fast pyrolysis technology. The mixed-integer linear programming model developed identifies the optimal biofuel production and biomass harvesting schedule schemes under the objective of profit maximization. It was applied in the case study of marginal lands in Scotland, which are assumed to be planted with Miscanthus. The trade-offs observed between economies of scale against the transportation costs, the effect of the relocation costs and the contribution of storage capacity were investigated. The results showed that, in most cases, harvesting is most concentrated during the month of the highest biomass yield, provided that storage facilities are available. Storage capacity plays an important role to widen the operational time window of processing facilities since scenarios with restricted or costly storage resulted in facilities of higher capacity operating within a narrower time window, leading to higher investment costs. Relocation costs proved to have a minor share in the total transportation costs.

Kenics Static Mixer Combined with Gas Sparging for the Improvement of Cross-Flow Microfiltration: Modeling and Optimization.

The use of membrane filtration as a downstream process for microbial biomass harvesting is hampered due to the low permeate flux values achieved during the microfiltration of fermentation broths. Several hydrodynamic methods for increasing permeate flux by creating turbulent flow patterns inside the membrane module are used to overcome this problem. The main goal of this study was to investigate the combined use of a Kenics static mixer and gas sparging during cross-flow microfiltration of Bacillus velezensis IP22 cultivation broth. Optimization of the microfiltration process was performed by using the response surface methodology. It was found that the combined use of a static mixer and gas sparging leads to a considerable increase in the permeate flux, up to the optimum steady-state permeate flux value of 183.42 L·m−2·h−1 and specific energy consumption of 0.844 kW·h·m−3. The optimum steady-state permeate flux is almost four times higher, whilst, at the same time, the specific energy consumption is almost three times lower compared to the optimum results achieved using gas sparging alone. The combination of Kenics static mixer and gas sparging during cross-flow microfiltration is a promising technique for the enhancement of steady-state permeate flux with simultaneously decreasing specific energy consumption.

The efficiency of microalgae-based remediation as a green process for industrial wastewater treatment

Wastewater treatment including microalgae is an economically promising and environmentally friendly alternative to conventional wastewater treatment due to the concurrent nutrient removal and production of high-value biomass. This work aimed to choose the most suitable type of wastewater and its appropriate dilution for sustaining microalgal growth by testing unialgal versus mixed microalgae cultures and raw versus autoclaved wastewater. Based on pilot experiments including microplate screening, unialgal cultures of Chlorella emersonii grown in 1:5 diluted, non-autoclaved wastewater were selected as the optimum scenario for further testing. In the main experiments, Chlorella emersonii was cultivated in Erlenmeyer flasks and bubble column reactors. Additionally, a photoautotrophic biofilm was grown in flumes. We studied three types of wastewater originating from a large municipal wastewater treatment plant, a brewery, and a dairy. Dairy wastewater performed best in all cultivation systems and resulted in a maximum biomass per irradiated area of around 145 μg cm−2 chlorophyll-a of Chlorella cultures in bubble columns, followed by 105 μg cm−2 in flumes run by a photoautotrophic biofilm. Furthermore, phosphorus reduction of 96 % for dairy, 40 % for the brewery, and 43 % for municipal wastewater were achieved in the flumes. Due to the easy harvest of algae biomass, low construction and operation costs, flumes represent a recommendable cultivation system for dairy wastewater treatment on a larger scale.

Human Appropriation of Net Primary Production Related to Livestock Provisioning Ecosystem Services in Southern Patagonia

Human appropriation of net primary productivity (HANPP) integrates ecological and socioeconomic perspectives on land use by quantifying the amount of net primary production (NPP) appropriated by society through biomass harvest from the ecosystem. The main objective of this study was to determine the spatial patterns of HANPP related to lamb and wool production from sheep farms across the province of Santa Cruz. The HANPP was obtained by dividing the sum of the biomass used in livestock products (lamb and wool) by the NPP. In addition, we examined the spatial relationship between HANPP and potential plant biodiversity and net carbon balance at the farm level under livestock land use across our study region. At the regional level, livestock production accounted for an average of 11.35% of appropriated NPP, and HANPP ranged from 0.75 to 50%. The map of HANPP across Santa Cruz showed low values in the vegetation transition (ecotone) between Nothofagus antarctica forests and grasslands in the west, in the south, and in wetlands where the most productive rangelands dominate. High values were observed in the northwest and central areas of the province. There were differences in HANPP across vegetation types with mean values that varied from 3.93% in grasslands on the Humid Magellanic Steppe to 12.33% in the Central Plateau. Simple linear regression analysis for HANPP evaluated in Southern Patagonia showed a negative linear relationship (p < 0.05) with vascular plant biodiversity and net carbon balance at the farm level. The method used to map HANPP related to livestock provisioning ecosystem services (ES) in the present study (lamb and wool), may be integrated into decision support systems. In this context, low HANPP values (<9%) promote sustainability-oriented economies within the region. Furthermore, keeping plant biodiversity and net carbon balance at the farm level could bring Patagonian export commodities recognition in international markets.

A circular approach for the efficient recovery of astaxanthin from Haematococcus pluvialis biomass harvested by flocculation and water reusability

Flocculation has been proved an efficient method for microalgal biomass harvesting, but some coagulant agents may have adverse effects on microalgae growth, making the reuse of the medium unfeasible. In this study, Haematococcus pluvialis was harvested by different flocculants, and the feasibility of the reuse of the culture medium was evaluated. Results suggested that both inorganics, polyaluminum chloride (PA) and ferric chloride (FC), and organics, extracted from Moringa oleifera seed (MSE) and chitosan (CH) resulted in efficient flocculation – flocculation efficiency above 99 %. However, using PA and FC had adverse effects on the astaxanthin recovery from haematocysts – losses of 58.6 and 73.5 %, respectively. Bioflocculants in the reused medium also had higher growth performance than inorganic ones. Furthermore, bioflocculants in reused medium increase the contents of β-carotene, astaxanthin, and linolenic acid. This investigation demonstrated that using MSE and CHI for harvesting H. pluvialis enables the water reusability from a flocculated medium.

Characteristics of forest biomass harvesting operations and markets in Virginia

Increased markets for renewable energy feedstocks have led to an expansion of the woody biomass industry in the Southeastern United States. Virginia has had biomass markets for several decades and provides an opportunity to study both producer and market characteristics. A survey was conducted among biomass harvesting business owners in Virginia designed to characterize harvesting operations and markets, assess business owner opinions related to the current and future state of the industry, and update/expand the results of a previous survey from 2014. Biomass harvesting operations in Virginia were generally conventional single crew roundwood operations utilizing their own residues for biomass. Production levels varied widely with biomass comprising an average 31% of total production. Material was comminuted utilizing large (485 median kW) older (13.2 years average) whole-tree chippers fed by a single loader. Coastal Plain operations were larger scale than Piedmont operations, though those in the Piedmont had been in business longer. Businesses had a median of $400,000 USD invested in biomass production equipment, which was double their median investment in the previous survey. Logging businesses that had produced biomass longer were significantly more likely to report profiting from biomass. In addition, loggers derived numerous non-monetary benefits from biomass production (e.g., improved aesthetics and cleaner sites, leading to increased landowner satisfaction), with most business owners planning to continue production in the future. This study provides stakeholders an overview of the current state of biomass harvesting businesses in Virginia and a discussion on benefits loggers derive from biomass markets.