Biomass Production Rate Research Articles

Novel effective bioprocess for optimal CO2 fixation via microalgae-based biomineralization under semi-continuous culture

In this study, the effects of microalgae-based biomineralization in a semi-continuous process (M-BSP) on biomass productivity and CO2 fixation rate were investigated. M-BSP significantly improved biomass production and CO2 fixation rate at the second stage of induction by sustaining relatively high photosynthetic rate without exposure to toxic substances (e.g., chlorellin) from aging cells using the microalgae Chlorella HS2. In conventional systems, cells do not receive irradiated light evenly, and many cells age and burst because of the long culture period. In contrast, in the M-BSP, the photosynthesis efficiency increases and biomass production is not inhibited because most of the cells can be harvested during shorter culture period. The accumulated biomass production and CO2 fixation rate of the HS2 cells cultured under M-BSP increased by 4.67- (25 ± 1.09 g/L) and 10.9-fold (30.29 ± 1.79 g/L day−1), respectively, compared to those cultured without the CaCl2 treatment.

Development of operating process for continuous production of biomass by Tetradesmus obliquus (MT188616.1) in a hollow fiber membrane photobioreactor

An effective prototype of photobioreactor namely hollow fiber membrane bioreactor is employed to produce algal biomass for biofuel production. The effect of two-stage cultivation system on the biomass productivity and lipid production is studied using freshwater green microalga Tetradesmus obliquus MT188616.1. The hybrid system combines exponential biomass production in hollow fiber membrane photobioreactor (HFMPBr) and a coordinated high-lipid stimulation phase in nitrogen-deprived medium by the shake flask method. This work is proposed to examine the usefulness of HFMPBr module to enhance the microalgal growth rate through the effective mass transfer by standardizing the culture medium re-circulation flow rates (5 – 45 mL min−1) through the hollow fiber membranes. Cultivation is carried out at continuous mode in HFMPBr containing polysulfone fabricated membranes at fixed light intensity of 50 µmol m−2 s−1 and temperature at 28 °C. Biomass productivity and specific growth rate obtained are 0.44 g L−1d−1 and 1.61 µ d−1 with a lipid yield of 0.1 g L− 1. The key operating parameter i.e., liquid flow rate is optimized based on biomass production. The highest biomass concentration is produced at the flow rate of 45 mL min−1. The results showed that HFMPBr module is a better choice for the algal-cultivation to obtain higher biomass yield.

Genetic Progress for Yield and Yield Components and Reaction to bean Anthracnose (Colletotrichum lindemuthianum) of Medium Sized Food Type Common Bean (Phaseolus Vulgaries L.) in West Shoa Zone, in Ethiopia

Eleven common bean (Phaseolus Vulgaris L.) varieties that were released in Ethiopia from 1998 to 2014 were evaluated as medium seeded food type common bean varieties. The objectives of this study were to: (1) estimate the genetic progress made in 16 years of common bean breeding in Ethiopia; (2) assess changes in associated traits in the genetic improvement of common bean varieties released in Ethiopia; and (3) assess the reaction of common bean varieties to bean anthracnose [Clletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara]. The study was conducted at two locations, Bako and Gute during the 2014/2015 cropping season in a randomized complete block design (RCBD) with three replications. Days to 50% flowering (DF), Days to 90% maturity (DM), Grain filling period (GFP), Hundred Seed weight (HSW), Biomass yield (BMY), Grain yield per plot (GY), Harvest index (HI), Biomass production rate (kg/ha/day), Seed growth rate (kg/ha/day), Grain yield per day (kg/ha/day) and Anthracnose (1-9) scale data were collected on plot basis and Plant height, Number of pods per plant, Number of seeds per pod, Number of seeds per plant and grain yield per plant data’s were collected on a plant basis. Combined analysis of variance showed highly significant differences among the common bean varieties and between test environments for hundred seed weight. The variety by location (VXL) interaction showed highly significant differences in biomass yield, harvest index, days to flowering, grain filling period, and biomass production rate. Regression analysis of mean performance at both environments on year of varietal release showed positive relationship for Gran yield (r = 0.08), Seed weight (r = 0.08) and Harvest index (r = 0.4) but negative relationship for Biomass yield (r = 0.04) and anthracnose disease severity (r = 0.016). The highest mean grain yield was 3008.7 kg ha-1 for the Haramaya variety and the lowest was 1708.8 kg ha-1 for Ada, with an overall mean of 2271.1 kg ha-1. The annual rate of genetic progress was 22.3 kg ha-1 (0.31% ha-1), 0.56g 100 seeds-1 year-1, 0.006%, 0.19%, and -60 kg ha-1 year-1 for grain yield, seed weight, harvest index, anthracnose disease severity, and biomass yield respectively. Generally, grain yield was slightly increased in the period of genetic improvement. Grain yield day-1 (90%) character explained more for the variation of grain yield but, anthracnose disease severity played the major role as grain yield did not respond significantly increment by (-33%) than seed weight (-0.01%) from stepwise regression results. The yield of medium seeded food type common bean varieties was increased due to grain yield day-1 for the past sixteen years (1998-2014) of breeding. The future crucial consideration will be managing the disease, like anthracnose disease for this common bean class and finally, Haramaya (3008.7 kg ha-1), SER- 125 (2954.8 kg ha-1), and SER-119 (2653.1 kg ha-1) will be recommended for the study area.

Intergenerational effects of ocean acidification on reproductive traits of an estuarine copepod

Copepods are an important part of the marine food web because of their high biomass productivity and nutrient turnover rate compared to other zooplankton in the marine ecosystem. Despite their great ecological role in the ocean, there is only limited information available on the consequences of ocean acidification (OA) induced by the future increase in CO2 on the planet. More specifically, there is almost no information about the impact of OA on the European copepod Calanipeda aquaedulcis Kritschagin, 1873. Therefore, the present investigation hypothesized that OA would not produce negative multigenerational effects on the survival and reproductive performance of this copepod species. Here we assessed, the multigenerational (F1 and F2) effect of OA on eight important reproductive traits (maturity, prosome length, fertility, egg release, hatching success, survival rate, reproductive performance, and the total number of adults per generation). For this study, C. aquaedulcis were collected from the Guadalquivir River (southwest of Spain) and were exposed to four different pH gradients (pH 8.1 as control and pH 7.5, 7.0, 6.5 as acidified conditions) to mimic the future seawater acidification scenarios. The survival rate from nauplius to adult, C. aquaedulcis was significantly reduced by pHs and across generations. Besides, results also indicated that there were marked effects on fertility, reflected by a significantly lower number of eggs per female in each generation. Similarly, hatching success also showed a decreasing pattern towards low pH, and importantly, F1 females had lower hatching success than F0 females. While a beneficial parental effect was detected in the offspring in response to OA, it was insufficient to offset the negative effects caused by it. The findings presented here appear to have ecological significance, as decreasing the reproductive performance of copepods may have a negative impact on the marine food web, as ichthyofaunal feeding and growth are heavily reliant on this component of the food web.

Suitability of pre-digested dairy effluent for mixotrophic cultivation of the hydrogen-producing microalgae Tetraselmis subcordiformis

ABSTRACT The costs associated with microalgal biomass production can be reduced by leveraging alternative and cheap growth media. Digestate from fermentation reactors is a particularly interesting candidate for use in cultivating mixotrophic species. The aim of the present study was to assess whether pre-digested milk-industry effluent can be harnessed to grow Tetraselmis subcordiformis and produce hydrogen. The experimental series with 25% and 50% effluent in the growth medium performed the best, producing more than 2000 mgVS biomass/dm3. The biogas produced in these variants contained over 60% hydrogen. Increasing the effluent in the medium to 75% led to significant deterioration of performance, both in terms of T. subcordiformis biomass growth and biohydrogen production. The highest efficiency of nitrogen and phosphorus removal, respectively 98.1 ± 1.9% and 97.1 ± 1.4%, was observed in the system to which 25% of sewage was introduced. Increasing the share of fermented wastewater directly reduced the efficiency of removing biogenic compounds. A very strong negative correlation was found between initial N-NH4 in the growth medium and T. subcordiformis biomass production rates (R2 = 0.9177).

The role of nocturnal fishes on coral reefs: A quantitative functional evaluation.

The ecological functions of nocturnal coral reef fishes are poorly known. Yet, nocturnal resources for coral reef consumers are theoretically as abundant and productive, if not more so, than their diurnal counterparts. In this study, we quantify and contrast the energetic dynamics of nocturnal and diurnal fishes in a model coral reef ecosystem, evaluating whether they attain similar levels of biomass production. We integrated a detailed dataset of coral reef fish counts, comprising diurnal and nocturnal species, in sites sheltered and exposed to wave action. We combined somatic growth and mortality models to estimate rates of consumer biomass production, a key ecosystem function. We found that diurnal fish assemblages have a higher biomass than nocturnal fishes: 104% more in sheltered sites and 271% more in exposed sites. Differences in productivity were even more pronounced, with diurnal fishes contributing 163% more productivity in sheltered locations, and 558% more in exposed locations. Apogonidae dominated biomass production within the nocturnal fish assemblage, comprising 54% of total nocturnal fish productivity, which is proportionally more than any diurnal fish family. The substantially lower contributions of nocturnal fishes to biomass and biomass production likely indicate constraints on resource accessibility. Taxa that overcome these constraints may thrive, as evidenced by apogonids. This study highlights the importance of nocturnal fishes in underpinning the flow of energy and nutrients from nocturnal resources to reef communities; a process driven mainly by small, cryptic fishes.

Biofixation of CO2 and biomass production from model natural gas using microalgae: An attractive concept for natural gas sweetening

Despite the fact that natural gases are the most vital source of energy, pollutants like carbon dioxide in natural gases cause sediment and erosion of equipment, catalysts poisoning, and the most important environmental pollution. Microalgae also have the ability to remove CO2 from some gas streams. In this work, for the first time, a species of microalgae is used to fix carbon dioxide from the natural gas stream that contain 7% (v/v) CO2. Therefore, the effect of different strategies of model gas injection, light intensity, and light/dark cycle on the biomass productivity, carbon dioxide fixation rate, and lipid and chlorophyll content of Chlorella sp. were investigated. The results showed that when the model gas was injected in the dark period, biomass productivity and carbon dioxide fixation rate reached the highest level. In point of fact, under light intensity of 300 µmol photon m-2s-1 the fixation rate has reached 240 mg L-1 day-1. In addition, both using nitrogen as a model gas balancer and higher level of light intensity arose increased productivity and fixation. Also, the combination of increased light intensity and model gas injection in the dark cycle provided a condition in which higher rates of lipid accumulation were induced. The highest lipid content observed in this condition was 42% obtained. Aeration using nitrogen as a model gas balancer decreased lipid production.

Temperature regulation schemes for improving biomass productivity and nutrient removal rate in outdoor raceway ponds

This study investigated the possibility of enhancing the biomass productivity and nutrient removal of microalgae grown in raceway ponds through temperature regulation. Scenedesmus sp. grown in anaerobically digested abattoir effluent (ADAE) was cultivated outdoor in eight raceway ponds. Seven ponds were subjected to different temperature regulation schemes (from 15 °C to 25 °C) and varying control windows (from 24 h to daytime-only). From the results of this study, an approximate 60 % increase in biomass productivity was observed for ponds operated at a minimum temperature of 15 °C coupled with a 24 h (T15P24) and 12.5 h (T15P12.5) control period in relation to the uncontrolled temperature pond (UTP). Generally, Scenedesmus ponds operated at 15 °C used 60 % less energy for heating, were more efficient in nutrient removal, and showed significantly higher biomass productivities with respect to the uncontrolled/higher temperature regulated ponds. In other words, significant productivity improvements were observed for the systems with lower energy demands.

Alternative strategies to perform solid-state cultivation in a multilayer packed-bed bioreactor: Continuous and cyclic operations

The packed-bed bioreactor (PBB) is one of the equipment most used in solid-state cultivation (SSC) processes. However, PBBs present problems in the removal of metabolic heat generated by microorganisms, making difficult to scale up these equipment, that are usually operated in batches. Aiming to minimize the overheating problems and to provide more versatility for biorefineries, this work aimed to evaluate alternative modes of operation of a multilayer PBB applied in the production of endoglucanase by SSC, namely cyclic and continuous operations. For this purpose, the fungus Myceliophthora thermophila I-1D3b was used as inoculum and sugarcane bagasse and wheat bran were used as substrates. In the cyclic operation, the layers had their positions changed every 24 h. In the continuous process, newly inoculated layers were added and spent layers fermented were removed every 24 h, leading to a regular flow of layers. Maximum temperatures reached 48.1, 48.2 and 48.3 °C and endoglucanase productivities were 2.85, 3.18 and 3.35 U/g of dry solid/h for classical, cyclic and continuous operations, respectively. These results showed no significant difference according to the Tukey test (α = 0.05). Despite that, in the continuous operation, the maximum CO2 concentration recorded was 60% lower than in batch operations. In addition, it was possible to estimate the biomass production rate in continuous operation, which was 5.32 g/h. Therefore, the continuous operation proved to be applicable and advantageous, being able to contribute to the scale up and operational versatility of PBBs and, consequently, to the industrial advancement of SSC.

Reclamation of nutrients, carbon, and metals from compromised surface waters fated to the Salton Sea: Biomass production and ecosystem services using an attached periphytic algae flow-way

The Salton Sea in the Imperial Valley of California is a threatened ecosystem. To address the challenges related to trace element accumulation and eutrophication, a 270 m long attached periphytic algae flow-way was deployed at the Alamo River Wetlands, a tributary of the Salton Sea. To assess opportunities for efficient generation of biomass from reclamation of run-off-derived nutrients, the quantities of available and biosorpbed nutrients, organics, and trace elements were monitored. Over the course of 2 years, persistent algal biomass production was achieved at an average ash-free biomass productivity of 5.8 ± 2.7 g/m2/day for the full flow-way length. Overall, harvested biomass consisted of high ash (76.3 ± 5.4%) and low lipid (1.1 ± 1.0%) content, which are typical of periphytic algal biomass. Nitrogen removal rates of 530 ± 190 mg N/m2/day, phosphorous removal rates of 14 ± 6 mg P/m2/day, and 73 ± 25% of BOD (Biological Oxygen Demand) removal rates were achieved. Furthermore, spatial variations of the biomass productivity along with nutrient removal rates were observed to have a decreasing trend over the length of the flow-way, while N and P contents of the biomass showed increasing trend, indicating variable nutrient utilization efficiency as an important factor for system scaling. Temperature and solar irradiation were found to be key environmental factors for biomass productivity and nutrient removal rates. However, stable uptake of nutrients, organics, and metals in the biomass, despite intermittent variation of the analyte concentrations in the source water, indicate the resilience of attached periphytic algae biomass production at dilute nutrient concentration regimes. Trace metal analysis of the water from the surrounding area revealed levels exceeding federal toxicity guidelines for Selenium and Copper. Significant bioaccumulation of these and other metals contaminants were also identified in the harvested biomass, including Nickel, Chromium, Cadmium and Lead. Together these findings demonstrate several potential value propositions for attached algae cultivation from agricultural runoff-impacted surface waters, including remediation of N/P nutrients, organics, and common toxic metals, concomitant with biomass production.

Evolution of an intermediate C4 photosynthesis in the non-foliar tissues of the Poaceae.

Carbon concentrating mechanisms (CCMs) in plants are abaptive features that have evolved to sustain plant growth in unfavorable environments, especially at low atmospheric carbon levels and high temperatures. Uptake of CO2 and its storage in the aerenchyma tissues of Lycopsids and diurnal acidity fluctuation in aquatic plants during the Palaeozoic era (ca. 300Ma.) would represent the earliest evolution of a CCM. The CCM parts of the dark reactions of photosynthesis have evolved many times, while the light reactions are conserved across plant lineages. A C4 type CCM, leaf C4 photosynthesis is evolved in the PACMAD clade of the Poaceae family. The evolution of C4 photosynthesis from C3 photosynthesis was an abaptation. Photosynthesis in reproductive tissues of sorghum and maize (PACMAD clade) has been shown to be of a weaker C4 type (high CO2 compensation point, low carbon isotope discrimination, and lack of Rubisco compartmentalization, when compared to the normal C4 types) than that in the leaves (normal C4 type). However, this does not fit well with the character polarity concept from an evolutionary perspective. In a recent model proposed for CCM evolution, the development of a rudimentary CCM prior to the evolution of a more efficient CCM (features contrasting to a weaker C4 type, leading to greater biomass production rate) has been suggested. An intermediate crassulacean acid metabolism (CAM) type of CCM (rudimentary) was reported in the genera, Brassia, Coryanthes, Eriopsis, Peristeria, of the orchids (well-known group of plants that display the CAM pathway). Similarly, we propose here the evolution of a rudimentary CCM (C4-like type pathway) in the non-foliar tissues of the Poaceae, prior to the evolution of the C4 pathway as identified in the leaves of the C4 species of the PACMAD clade.

Wastewater-Fertigated Short-Rotation Coppice, a Combined Scheme of Wastewater Treatment and Biomass Production: A State-of-the-Art Review

Vegetated filters based on short-rotation coppice (SRC) can be used to treat various industrial and municipal wastewater while producing valuable biomass in an economical and sustainable way, showing potential in the field of pollution control and bio-based circular economy. This study provides an overview of the state of the art in wastewater-fertigated SRC systems (wfSRCs) worldwide. Different designs, wastewater sources, tree species and varieties, planting schemes, geographic locations, and climates for wfSRC implementation were identified after conducting a literature review. The performance review includes standard water quality parameters, BOD5, COD, nitrogen, phosphorous, and potassium, as well as the extent of pathogen and emergent contaminant removal and biomass production rates. Identified knowledge gaps and important factors to support the practical implementation of wfSRCs are highlighted. Europe leads the research of wfSRC, followed by North America and Australia. The available publications are mainly from developed countries (73%). The most applied and studied tree species in wfSRC systems are willows (32%), followed by eucalyptus (21%) and poplars (18%). Most of the reviewed studies used domestic wastewater (85%), followed by industrial wastewater (8%) and landfill leachate (7%). Most data show high BOD5 and COD removal efficiencies (80%). There are large differences in the documented total nitrogen and total phosphorus removal efficiencies (12%–99% and 40%–80%, respectively). Enhanced biomass growth in wfSRC systems due to wastewater fertigation was reported in all reviewed studies, and biomass production varied from 3.7 to 40 t DM/ha/yr. WfSRCs seem to have high potential as viable and cost-effective wastewater treatment alternatives to conventional treatment technologies.

Effects of biochar derived from the pyrolysis of either biosolids, manure or spent coffee grounds on the growth, physiology and quality attributes of field-grown lettuce plants

The positive effects of biochar applied as soil conditioner for boosting soil fertility and thus plant growth are sufficiently documented, mostly through in-situ experimentation. This field study evaluated the effects of soil amendment (5% v/v) with distinct types of biochar (biosolids-derived biochar, BDB; cattle manure-derived biochar, MDB; spent coffee grounds-derived biochar, SCGDB) on the growth, physiology and quality attributes of lettuce ( Lactuca sativa L.) plants grown in sandy clay loam-textured soil, under temperate climatic conditions. Peat moss (PM) was also used, to serve as internal control due to its wide use. Plants grown on MDB-amended soil showed a significant increase of biomass production rate, evident through elevated mean fresh and dry weight values compared with all other treatments. Increased growth was also found in BDB treatment, though failed to reach significance. None of the treatments impacted the photosynthetic pigment content, however they did reduce the nitrates content in leaves. Leaves sampled from BDB and MDB treatments showed reduced soluble solids content (SSC) and titratable acidity (TA), and increased sucrose content. MDB-treated plants showed increased fructose content while BDB-treated plants showed increased total soluble sugar and total phenolics content. Moreover, plants grown in MDB- and BDB-amended soil showed increased total antioxidant capacity, despite maintaining ascorbic acid content in values similar to control. SCGDB and PM treatment did not affect any of the parameters tested. Overall, results showed that BDB and MDB applied as soil amendments may serve as means for enhancing the growth, and partially the nutritional value of lettuce plants. • Distinct biochars were used as soil amendments in lettuce grown in low fertile soil. • Lettuce plants in soil amended with manure-derived biochar had increased biomass. • Applied biochars did not impact the photosynthetic pigment content of leaves. • Manure- and biosolids-derived biochar enhanced the antioxidant capacity of plants. • Manure- and biosolids-derived biochar performed better compared with peat moss.

EFFECT OF NaCl CONCENTRATION ON THE PRODUCTION OF Arthrospira maxima CULTIVATED IN THE HUMID TROPICS

The production of microbial biomass can be affected by the composition of the culture medium, including the content of salts and there is little information in terms of the NaCl concentration. Therefore, in this study, the effect of the addition of different NaCl concentrations (0.0, 2.0, 2.5, and 3.0 g L-1) in a Jourdan medium was evaluated on cell growth and physical and chemical properties of Arthrospira maxima cultivated in the region of Cordoba, Veracruz, Mexico. The experiment was established under a completely randomized design with a factorial arrangement (AxB). During the production stage, cell growth and morphology of filaments were evaluated, and after harvesting, the physical and chemical analysis (moisture, crude fiber, total protein and lipid content, mineral composition, photosynthetic compounds, antioxidant activity, and structural composition through FTIR-Spectroscopy analysis) of A. maxima was performed. Results obtained show that the addition of NaCl did not affect cell development, the morphology of the filaments, or the content of photosynthetic compounds. The maximum rate of biomass production in all treatments was at 6 d, without significant differences (p > 0.05) among treatments. In all treatments, A. maxima showed adequate concentrations of protein and minerals, as well as antioxidant activity. FTIR spectra showed absorption bands associated with proteins, carbohydrates, lipids, and nucleic acids. A decrease in the amide I and amide II bands of the proteins was observed with the addition of NaCl. A. maxima cultivated in these tropical climatic conditions had excellent properties to be used as a functional ingredient in the development of innovative and biotechnological food products for human consumption.

Effects of Soil Amendments on Metal Uptake, Antioxidant Activities and Production of Bioactive Compounds by Sunflower Sprouts

The effects of soil amendments on Cd and Zn uptake, bioactive compounds and antioxidant activities in two cultivars (Pacific 33 and Black Oil) of Helianthus annuus L. were evaluated. Dicalcium phosphate/cattle manure and leonardite/cattle manure mixed in a 1:1 w/w ratio with soil served as soil treatments. The Black Oil cultivar experienced greater metal uptake, biomass production and survival rate compared to the Pacific 33 cultivar. The increased Cd and Zn uptake (>0.2 and >99.4 mg/kg, respectively) in Black Oil cultivar exceeded the regulatory standard for vegetables. Significantly higher levels of bioactive compounds and antioxidant activities were detected in the control treatment for Pacific 33 leaves compared to Black Oil cultivar. Synergistic effects of heavy metals, amendment application and plant genotype are considered key factors in decreased levels of bioactive compounds and antioxidant activities.

Effect of photoperiods and CO2 concentrations on the cultivation of carbohydrate-rich P. kessleri microalgae for the sustainable production of bioethanol

Biofuels production from microalgal biomass has been investigated as an alternative approach to replace conventional fossil fuels, contributing to the reduction of greenhouse gas emissions. However, several constraints such as high cultivation and harvesting costs are still limiting the techno-economic viability of microalgae-based biofuels. The integration of wastewater and CO2 streams shows strong potential for lowering the process costs as well as the environmental impacts of conventional microalgal culture systems.In this study, 25 microalgae strains were individually screened for their ability to survive and grow under various CO2 concentrations ranging from 0.04% to 100%. After selecting the most resistant strain, cultivation assays were performed in 3.5 L bubble columns reactors to investigate the effect of different light/dark cycles (4 h/20 h, 12 h/12 h and 20 h/4 h) and CO2 concentrations (0.04%, 2.5%, 5.0% and 10%) on the algal growth properties, the CO2 fixation efficiency as well as the microalgal biochemical composition.The cultivation of Parachlorella kessleri microalgae in the presence of 2.5% (v/v) of pig manure combined with 5% CO2 and light/dark cycle of 20 h/4 h generated the highest specific growth rate (0.58 d−1), biomass productivity (104 mg/L/d) and CO2 fixation rate (211 mgCO2/L/d). These culture conditions triggered the accumulation of carbohydrates in P. kessleri microalgae, resulting in the highest carbohydrate content and productivity of 44.2% and 46.1 mg/L/d, respectively. Subsequently, the carbohydrate-rich microalgal biomass was successfully used as feedstock to produce bioethanol using Saccharomyces cerevisiae yeasts.

Assessment of Domestic Wastewaters as Potential Growth Media for Chlorella vulgaris and Haematococcus pluvialis

Domestic wastewater contains chemical compounds that can be used as nutrients for microalgae. Removing these chemical compounds from wastewater by microalgae might help in reducing the operation cost of wastewater management while minimizing the cultivation cost for large-scale microalgae metabolite production. In this study, domestic wastewater collected from Indah Water Konsortium (IWK), Kuala Lumpur, Malaysia, was assessed as growth media for two types of microalgae, namely Chlorella vulgaris and Haematococcus pluvialis. The biomass growth and nutrient removal efficiency of total nitrogen (TN), total phosphorus (TP), and total ammonia (TAN) in different concentrations of diluted wastewater were measured. The results showed that biomass concentration (0.227 g/L), biomass productivity (0.029 g/L/day), and specific growth rate (0,284 d-1) yielded by C. vulgaris in 14 days of 80% wastewater were comparable to those microalgae grew in standard Bold’s Basal medium (BBM). Besides, C. vulgaris grew in 50% wastewater to remove TN, TP, and TAN with the highest removal efficiency (>88%). For H. pluvialis, the biomass concentration in all wastewater concentrations was lower than BBM. The removal efficiencies of TN and TP were lower than 55%, but more than 80% for removal efficiency of TAN in 50% and 80% wastewater. Hence, C. vulgaris has better growth performance and nutrient removal efficiency than H. pluvialis. These findings indicated that IWK domestic wastewater could be used as growth media for microalgae, especially C. vulgaris.

Comparison of Kveik with Conventional Saccharomyces Brewing Strains for Propagation Characteristics, Biomass Production, and Biomass Conversion Rate​​

Comparison of Kveik with Conventional Saccharomyces Brewing Strains for Propagation Characteristics, Biomass Production, and Biomass Conversion Rate​​

Influence of pH on Water Hyacinth Ponds Treating and Recycling Wastewater

This work has examined the effects of pH on the treatment efficiency and biomass production rate of water hyacinth ponds (WHP) treating domestic wastewater. Experiments were carried out outdoor in WHP, working under batch and subtropical environmental conditions, using pre-treated sewage with pH varying from 5 to 9. It was observed that the plants regulated the pH of the medium to within 6.4 to 7.1 during the treatment processes independently of influent wastewater pH ranges. This adjustment reduced the treatment performances and the biomass production in ponds, the alkaline conditions in ponds being less favorable to the activities of the plants. The optimal removal and biomass production was achieved with influent pH of 7 lying in the above interval. So the optimum influent pH for the growth of plants and the removal of nutrients and organic matters in WHP is within pH 6.4 to pH 7.1.

Optimisation of Scenedesmus almeriensis production using pig slurry as the sole nutrient source

Pig slurry was used as the sole nutrient source to produce biomass of the microalga Scenedesmus almeriensis using laboratory-scale bubble column photobioreactors. No differences in terms of biomass productivity were observed between fresh and digested pig slurry. The optimum dilution of the slurry to enable the processing of the largest amount of pig slurry per litre was 5%, which led to a biomass productivity rate of 0.68 g·L−1·day−1, comparable to that of the standard growth medium formulated using pure chemicals (0.70 g·L−1·day−1). The inlet N-NH4+ concentration was approximately 180 mg·L−1, with inhibitory effects being observed at concentrations higher than 200 mg·L−1. The N-NH4+, N-NO3−, P-PO43−, and chemical oxygen demand removal rates were 34.1, 0.5, 2.1, and 519.3 mg·L−1·day−1. The observed turbidity of the media did not affect microalgal growth at the studied dilutions. Ozonation effectively reduced the chemical oxygen demand concentration of the media, but no effect on microalgal growth was observed. Overall, pig slurry was an effective nutrient source for the production of S. almeriensis, and this strain was shown to be robust with a N-NH4+ tolerance up to 200 mg·L−1 and the potential use in the bioremediation of agro-industrial wastes.