Zheng Sun

Shanghai Ocean University | SHOU · Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education of China

A new MLDP isoform of M. incisa was identified and characterized ¬ Predicted subcellular localization of MiMLDP was experimentally validated ¬ Heterologous expression of MiMLDP promoted triacylglycerol production in yeast ¬ MiMLDP was responsible for enlarged lipid droplets and reduced steryl esters

Myrmecia incisa is a valuable microalga worth investigating as it is rich in arachidonic acid (ArA), a polyunsaturated fatty acid that is essential for human health. The present study developed a two-stage cultural strategy for M. incisa. In stage Ⅰ, heterotrophic mode was conducted for the purpose of high algal biomass production. By determining t...

Phaeodactylum tricornutum, a model alga, is well known for its ability to accumulate intracellular omega-3 eicosapentaenoic acid (EPA). However, P. tricornutum cells need to have a higher EPA content if they are to be used for industrial applications. In this study, an auxin-like supermolecule (SM) was synthesised and used for the cultivation of P....

Microalgae have important applications in the aquaculture industry due to their remarkable nutritional value, especially the high contents of carotenoids. In this study, five microalgae, including Spirulina sp., Dunaliella salina, Haematococcus pluvialis, Isochrysis galbana and Parietochloris incisa were investigated for their beneficial effects on...

Microalgae represent a rich and naturally occurring source of triacylglycerol (TAG), and the microalgae-derived TAG has enormous potential in bioenergy, bio-based materials and other agricultural innovations. Glycerol-3-phosphate acyltransferase (GPAT) is a key enzyme that catalyzes the biosynthesis of TAG. Previously our lab has reported the first...

Dunaliella salina is a promising microbial host for the sustainable production of bioenergy and valuable compounds. D. salina can be mixotrophically cultivated using a pure organic carbon source. However, pure organic carbon sources remarkably enhance the cost of cultivation and constrain the development of upscale microalgal cultivation. This stud...

The green alga Myrmecia incisa is rich in arachidonic acid (ArA), which mainly stores in lipid droplets in the form of triacylglycerol (TAG). In the de novo biosynthesis of TAG, diacylglycerol acyltransferase (DGAT) catalyzes the final and committed step as a rate-limiting enzyme. Previously, our lab has reported the first DGAT in M. incisa, and in...

Bioconversion of food waste into value-added products is a promising way to tackle the global food waste management problem. In this study, a novel valorisation strategy for bioenergy and lutein production via microalgal fermentation was investigated. Significant amount of glucose was recovered from enzymatic hydrolysis of food waste. The resultant...

Abstract Biorefining of microalgae biomass requires processing of high-solids (> 10%) slurries. To date there is little knowledge of how processes for weakening and rupturing microalgae cells affect the rheological properties of these materials. To fill this gap in the literature, the rheological properties of concentrated slurries of marine microa...

The growth and astaxanthin production of Chlorella zofingiensis were examined under both heterotrophic and photoautotrophic conditions, and it was found that compared with the photoautotrophic mode, the heterotrophic mode led to high algal densities but attenuated intracellular astaxanthin accumulation. Following the heterotrophy-photoautotrophy tr...

Chromochloris zofingiensis, featured by the capability of simultaneously synthesizing triacylglycerol (TAG) and astaxanthin, is emerging as a leading candidate alga for production uses. In order to better understand the oleaginous mechanism of this alga, we conducted a multi‐omics analysis by systematically integrating the time‐resolved transcripto...

The green alga Chlorella pyrenoidosa can accumulate lutein and chlorophyll under heterotrophic conditions. We propose that the mitochondrial respiratory electron transport chain (mRET) may be involved in this process. To verify this hypothesis, algal cells were treated with different mRET inhibitors. The biosynthesis of lutein and chlorophyll was f...

Isochrysis is a genus of marine algae without cell wall and capable of accumulating lipids. In this study, the lipid production potential of Isochrysis was assessed by comparing 15 Isochrysis strains with respect to their growth rate, lipid production, and fatty acid profiles. Three best strains were selected (lipid productivity, 103.0~121.7 mg L−1...

Producing biodiesel from microalgae grown in wastewater is environment-friendly and cost-effective. The present study investigated the algae found in wastewater of a local dairy farm for their potential as biodiesel feedstocks. Thirteen native algal strains were isolated. On the basis of morphology and 16S/18S rRNA gene sequences, one strain was id...

Managing waste is an increasing problem globally. Microalgae have the potential to help remove contaminants from a range of waste streams and convert them into useful biomass. This article presents a critical review of recent technological developments in the production of chemicals and other materials from microalgae grown using different types of...

The marine microalgae Isochrysis are a good producer of natural docosahexaenoic acid (DHA). To better understand the patterns of DHA accumulation and distribution, two Isochrysis strains, CL153180 and CCMP462, were evaluated in this study. In a batch culture, CL153180 showed a decline in DHA content while CCMP462 exhibited a progressive increase du...

The use of wastewater-grown algae for biofuel production is economical and eco-friendly. In the present study, an algal strain was isolated from the wastewater of a local dairy farm. On the basis of the morphology, ultrastructure, and 18S rRNA gene sequences, the specimen was identified to be conspecific with Choricystis minor Fott, which is a newl...

The green alga Myrmecia incisa is one of the richest natural sources of arachidonic acid (ArA). To better understand the regulation of ArA biosynthesis in M. incisa, a novel gene putatively encoding the Δ9 fatty acid desaturase (FAD) was cloned and characterized for the first time. Rapid-amplification of cDNA ends (RACE) was employed to yield a ful...

Microalgae are sunlight driven single-cell factories for protein, lipids, carbohydrates, pigments, vitamins and minerals, etc. Microalgae have long been used as health food and additives for human consumption, as well as animal feed in aquaculture. Microalgae also prove to be beneficial to environmental cleanup such as bioremediation of industri...

Microalgae represent a sustainable source of natural products, and over 15,000 novel compounds originated from algal biomass have been identified. This chapter focuses on algae-derived lutein, a group of high-value products. Lutein belongs to carotenoids which have extensive applications in feed, food, nutraceutical, and pharmaceutical industries....

Acyl-CoA: diacylglycerol acyltransferase (DGAT) is a key enzyme responsible for triacylglycerol (TAG) synthesis in eukaryotic organisms. The present work reported DGAT genes in the green alga Myrmecia incisa, a promising candidate for arachidonic acid (ArA) production. According to the results of homology search against a transcriptome database, we...

Extracellular polysaccharides (EPS) produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA) production, the yield of EPS remains relatively low. To...

Sargassum vachellianum is important in maintaining the structure and function of littoral ecosystems in China. In this study, we developed 12 polymorphic microsatellite markers in this species by 5′ anchored PCR technique. Across these markers, a total of 25 alleles were detected in a single population of 31 individuals of S. vachellianum. The numb...

Mixed food waste, which was directly collected from restaurants without pretreatments, was used as a valuable feedstock in succinic acid (SA) fermentation in the present study. Commercial enzymes and crude enzymes produced from Aspergillus awamori and Aspergillus oryzae were separately used in hydrolysis of food waste, and their resultant hydrolysa...

With the increasing awareness and concern about the dependency on fossil resources and the depletion of crude oil reserves, experts from industrial biotechnology, renewable resources, green chemistry, and biorefineries are stimulating the transition from the fossil-based to the bio-based economy. This text confronts scientific and economic challeng...

In this study, Halomonas boliviensis was cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB) production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized by Halomonas boliviensis while PHB contents between 10 and 30% (w/w) were obtained. Furth...

Astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most pro...

The unicellular green alga Chlorella zofingiensis has been proposed as a promising producer of natural astaxanthin, a commercially important ketocarotenoid. But the genetic toolbox for this alga is not available. In the present study, an efficient transformation system was established for C. zofingiensis. The transformation system utilized a modifi...

Microalgae are huge natural sources of high-value compounds with health-promoting properties. The carotenoids derived from microalgae have significant antioxidant and anti-inflammatory effects, which allow them to provide health benefits. In this article, the bioactivities of microalgal carotenoids are reviewed. Emphasis is placed on astaxanthin, a...

The aim of the present study was to survey the growth and astaxanthin production of E17, an astaxanthin-rich mutant of Chlorella zofingiensis, through feeding the low-cost carbon source cane molasses. In heterotrophic batch cultivation, E17 fed with pretreated molasses achieved biomass (1.79 g L−1 day−1) and astaxanthin (1.99 mg L−1 day−1) producti...

Algae have long been recognized as potential feedstock to produce oils. In recent years, the use of algae, in particular, Chlorella, for heterotrophic oil production has gained increasing interest due to its fast growth, ultrahigh cell density, and superior oil productivity. The current technology for heterotrophic production of algal oils, however...

The microalga Haematococcus pluvialis (HP) is the best natural producer of astaxanthin (AX), a potent antioxidant with broad health benefits. The present study investigated the anti-ageing potential of HP biomass using the fruit flies Drosophila melanogaster as the animal model. Results showed that in wild type flies, the treatment of HP induced th...

Glucose, free amino nitrogen (FAN), and phosphate were recovered from food waste by fungal hydrolysis using Aspergillus awamori and Aspergillus oryzae. Using 100 g food waste (dry weight), 31.9 g glucose, 0.28 g FAN, and 0.38 g phosphate were recovered after 24 hours of hydrolysis. The pure hydrolysate has then been used as culture medium and nutri...

In this paper, bakery waste, including cakes and pastries from Starbucks Hong Kong, was evaluated for the potential of succinic acid (SA) production. Through simultaneous hydrolysis and fungal autolysis, both cake and pastry hydrolysates were found to be rich in glucose (35.6 and 54.2 g L−1) and free amino nitrogen (685.5 and 758.5 g L−1), whereas...

Feruloylated oligosaccharides consist of a large group of compounds that are mainly produced from the hydrolysis of feruloylated polysaccharides. Some are commercially available in the market. In the bound form, ferulic acid is usually esterified at position C-2 or C-5 to l-arabinofuranosyl residues, at position C-6 to β-d-galactopyranosyl residues...

The green alga Chlorella zofingiensis can accumulate high level of oleic acid (OA, C18:1△(9)) rich oils in response to stress conditions. To understand the regulation of biosynthesis of fatty acid in particular OA at the molecular level, we cloned and characterized the stearoyl acyl carrier protein (ACP) desaturase (SAD) responsible for OA formatio...

The inhibitory effects of the green alga Chlorella pyrenoidosa against key enzymes relevant for type-2 diabetes were reported for first time in the present work. The alga exerted its anti-diabetic actions by scavenging free radicals and /or chelating transition metals but not by suppressing reactive carbonyl species. These findings strongly support...

The present study examined the antiglycative and antioxidant properties of four edible sprouts popular in Chinese markets. In a protein-reducing sugar model, the sunflower sprout Helianthus annuus exhibited the strongest inhibitory effects against the formation of advanced glycation end products (AGEs). At a concentration of 1.0 mg/mL, its inhibito...

Acrolein (ACR) is an α,β-unsaturated aldehyde that exists extensively in the environment and (thermally processed) foods. It can also be generated through endogenous metabolism. Its high electrophilicity makes this aldehyde notorious for its facile reaction with biological nucleophiles, leading to the modification of proteins/DNA and depletion of g...

The antiglycoxidative properties of microalga Chlorella zofingiensis were investigated for the first time in this study. Algal extracts containing different contents of astaxanthin were prepared. Through the comparison, it was shown that the extract rich in astaxanthin exhibited higher antioxidant abilities as well as stronger antiglycative capacit...

The formation and accumulation of advanced glycation endproducts (AGEs) is a key pathophysiological process involved in various diabetic complications such as diabetic retinopathy. In the present study, for the first time, protective effects of three microalgal strains, including their extracts and active compounds, against both endogenous and exog...

The objective of this study was to document and compare the lipid class and fatty acid composition of the green microalga Chlorella zofingiensis cultivated under photoautotrophic and heterotrophic conditions. Compared with photoautotrophic cells, a 900% increase in lipid yield was achieved in heterotrophic cells fed with 30 g L(-1) of glucose. Furt...

The lipid contents and fatty acid profiles of Chlorella zofingiensis cultured in the dark with various carbon sources were investigated. Glucose was found to be the best carbon source for the growth and lipid production. When cultivated with 50gL(-1) glucose, C. zofingiensis accumulated lipids up to 52% of the dry biomass, with triacylglycerols (TA...

Advanced glycation endproducts (AGEs) are a group of complex and heterogeneous compounds formed from nonenzymatic reactions. The accumulation of AGEs in vivo has been implicated as a major pathogenic process in diabetic complications and other health disorders, such as atherosclerosis and Alzheimer's disease, and normal aging. In this study, we inv...

The antiglycative activities of 20 microalgae at different growth phases were evaluated for the first time. In a bovine serum albumin (BSA)-glucose system, ethyl acetate fractions of green microalgae Chlorella and diatom Nitzschia laevis exhibited the highest inhibitoryeffects against the formation of total advancedglycationendproducts (AGEs) (inhi...

A stable Chlorella zofingiensis mutant (E17) produced by chemical mutagen was characterized with respect to growth, astaxanthin biosynthesis, and phytoene desaturation. The mutant E17 could grow well and produce normal levels of colored carotenoids in the presence of 0.25 microM norflurazon, in which the growth of wild type (WT) cells was greatly l...