Longyu Zheng

Developmental and Waste Reduction Plasticity of Three Black Soldier Fly Strains (Diptera: Stratiomyidae) Raised on Different Livestock Manures

ABSTRACT Black soldier flies, Hermetia illucens L., are distributed throughout the temperate and tropic regions of the world and are known an established method for sustainably managing animal wastes. Colonies used to conduct research on the black soldier fly within the past 20 yr have predominately been established from eggs or larvae received from a colony originated from Bacon County, GA. Consequently, little is known about the phenotypic plasticity (i.e., development and waste conversion) across strains from different regions. This study compared the development of three strains of the black soldier fly (Texas; Guangzhou, China; and Wuhan, China) and their ability to reduce dry matter and associated nutrients in swine, dairy, and chicken manure. The Wuhan strain appeared to be more fit. Larvae from Wuhan needed 17.7–29.9% less time to reach the prepupal stage than those from Guangzhou or Texas, respectively. Larvae from Wuhan weighed 14.4–37.0% more than those from Guanghzhou or Texas, respectively. Larvae from the Wuhan strain reduced dry matter 46.0% (swine), 40.1% (dairy), and 48.4% (chicken) more than the Guangzhou strain and 6.9, 7.2, and 7.9% more than the Texas strain. This study demonstrates that phenotypic plasticity (e.g., development and waste conversion) varies across populations of black soldier flies and should be taken into account when selecting and establishing a population as a waste management agent in a given region of the world.

Potential biodiesel and biogas production from corncob by anaerobic fermentation and black soldier fly

Bioenergy has become attractive as alternatives of gradually exhausted fossil fuel. Obtaining high grade bioenergy from lignocellulose is attractive that can gradually meet the demand. This study reported biogas and biodiesel were produced from corncob by a two-step bioprocess, biogas was produced from corncob by anaerobic fermentation, then biogas residue was converted by black soldier fly larvae, and then biodiesel was produced from larvae grease. 86.70 L biogas was obtained from 400 g corncob with the accumulation of biogas yield of 220.71 mL/g VS(added) by anaerobic digestion. Besides, 3.17 g of biodiesel was produced from grease after inoculating black soldier fly larvae into 400 g biogas residue. Meanwhile, the results showed that the addition of black soldier fly larvae could be effective for the degradation of lignocellulose and the accumulation of grease.

Insect Fat, a Promising Resource for Biodiesel

Biodiesel is one promising approach to reduce the consumption of petroleum. However, biodiesel economy has been hampered by the production of oilseed plants. Therefore, alternative feedstocks are urgently needed to enable biodiesel production from cheaper materials. Insect recourse which is rated as the most diverse animal group is rich and ubiquitous in the world. Insect could convert organic waste into insect fat which was further extracted as a novel feedstock for biodiesel production, and then the residual after extraction can be used as protein feedstuff. This paper reviewed the research and developmental progress on insect fat, especially the possibility of insect fat as potential feedstock of biodiesel.

Protecting the environment through insect farming as a means to produce protein for use as livestock, poultry, and aquaculture feed

Securing protein for the approximate 10 billion humans expected to inhabit our planet by 2050 is a major priority for the global community. Evidence has accrued over the past 30 years that strongly supports and justifies the sustainable use of insects as a means to produce protein products as feed for pets, livestock, poultry, and aquacultured species. Researchers and entrepreneurs affiliated with universities and industries, respectively, from 18 nations distributed across North and South America, Europe, Asia, Africa and Australia contributed to the development of this article, which is an indication of the global interest on this topic. A brief overview of insects as feed for the aquaculture industry along with a review of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), as a model for such systems is provided.

Cellulose decomposition and larval biomass production from the co-digestion of dairy manure and chicken manure by mini-livestock (Hermetia illucens L.)

World trends toward the modern dairies intensification on large production units cause massive animal manure production and accumulation. Improper handling of manure produced by industrial farm operation greatly deteriorates the major environmental media including air, water and soil. The black soldier fly utilizes organic waste and converts it into larvae biomass to be used as livestock feed and into residues to be used as bio-fertilizer. However, due to the high ratio of cellulose, hemicellulose and lignin in dairy manure, this conversion is difficult. Therefore, dairy manure treated with chicken manure was digested by Hermetia illucens. In this paper, we found that the co-digestion process significantly enhanced the larval production, waste mass reduction, rate of larvae conversion, feed conversion ratio, nutrient reduction and fibers utilization. Whereas 40% dairy manure and 60% chicken manure group show better results than other manure mixtures and had a significantly increased the cellulose consumption by 61.19%, hemicellulose consumption by 53.22% and lignin consumption by 42.23% compared with 49.89%, 49.77% and 31.95%, respectively, in the dairy-only manure group. Finally, scanning electron microscopy was used to analyze the structural changes of dairy manure, chicken manure and their co-digestion mixtures. The scan electron microscopy showed the deterioration in the structure of dairy and chicken manure fibers by Hermetia illucens. Moreover, the carbon-nitrogen ratio was decreased in all end products of post vermicomposting. The results suggest that the co-digestion of 40% dairy manure with 60% chicken manure is an appropriate proportion for dairy manure management with the black soldier fly.

Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.)

Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens.

Comparative genomic and functional analyses: unearthing the diversity and specificity of nematicidal factors in Pseudomonas putida strain 1A00316

We isolated Pseudomonas putida (P. putida) strain 1A00316 from Antarctica. This bacterium has a high efficiency against Meloidogyne incognita (M. incognita) in vitro and under greenhouse conditions. The complete genome of P. putida 1A00316 was sequenced using PacBio single molecule real-time (SMRT) technology. A comparative genomic analysis of 16 Pseudomonas strains revealed that although P. putida 1A00316 belonged to P. putida, it was phenotypically more similar to nematicidal Pseudomonas fluorescens (P. fluorescens) strains. We characterized the diversity and specificity of nematicidal factors in P. putida 1A00316 with comparative genomics and functional analysis, and found that P. putida 1A00316 has diverse nematicidal factors including protein alkaline metalloproteinase AprA and two secondary metabolites, hydrogen cyanide and cyclo-(l-isoleucyl-l-proline). We show for the first time that cyclo-(l-isoleucyl-l-proline) exhibit nematicidal activity in P. putida. Interestingly, our study had not detected common nematicidal factors such as 2,4-diacetylphloroglucinol (2,4-DAPG) and pyrrolnitrin in P. putida 1A00316. The results of the present study reveal the diversity and specificity of nematicidal factors in P. putida strain 1A00316.

Dynamic changes of nutrient composition throughout the entire life cycle of black soldier fly

Black soldier fly (BSF) larvae, Hermetia illucens L., develops on organic wastes, reducing ecological pollution and converting waste biomass into protein and fat rich insect biomass. BSF can replace increasingly expensive protein sources used in poultry, aquaculture and livestock compound diet formulation, such as fish meal and soybean meal, which holds the potential to alleviate future food and feed insecurity. The fate of nutritional spectra in BSF during its life cycle phases is still poorly understood. This study assessed metabolic changes in nutrition composition of BSF from egg to adult. A rapid increase of crude fat content was observed since the development of 4–14 days of larvae with its maximum level reaching 28.4% in dry mass, whereas the crude protein displayed a continuous decreasing trend in the same development phases with minimum level of 38% at larval phase (12 days) and peak level of 46.2% at early pupa stage. A sharp drop in crude fat was noticed from early prepupae to late pupae (24.2%, 8.2% respectively). However crude protein shows its maximum value being 57.6% at postmortem adult stage with 21.6% fat level. In addition, fatty acids, amino acids, minerals and vitamins composition in different development stages of BSF were presented and compared. Findings from this study could provide podium to food and feed industry for framing a strategy for specific molecular nutritional component intake into the diets of humans, aquaculture and animals. It is also indicated that BSF is a possible insect which can be applied to combating the food scarcity of countries where micronutrient deficiency is prevalent. Moreover it contributes to advance exploring for developmental and metabolic biology of this edible insect.

Resistance of black soldier fly (Diptera: Stratiomyidae) larvae to combined heavy metals and potential application in municipal sewage sludge treatment

Treating municipal sewage sludge (MSS) sustainably and economically in China remains a challenge because of risks associated with the heavy metals it contains. In this study, black solider fly larvae (BSFL) were used for MSS treatment. The resistance of larvae to combined heavy metals and their potential use in conversion of MSS were investigated. The results indicated that seven MSS samples contained large amounts of heavy metals, with the lead and nickel contents of several samples exceeding Chinese national discharge standards. BSFL were highly tolerant to an artificial diet spiked with combined heavy metals. Principal component analysis revealed that high concentrations of lead, nickel, boron, and mercury potentially interfered with larval weight gain, while zinc, copper, chromium, cadmium, and mercury slightly reduced larval survival. The addition of chicken manure and wheat bran as co-substrates improved the conversion process, which was influenced by the nature and amount of added co-substrate and especially the quantity of nitrogen added. With the amended substrate, the BSFL accumulated heavy metals into their bodies but not into extracted larval oil. The heavy metal content of the treatment residue was lower than that considered safe for organic-inorganic compound fertilizers standards in China and the harvested larvae could be used as a source of oil for industrial application.

Observations on the Oriental Latrine Fly, Chrysomya megacephala 1 in the McFaddin National Wildlife Refuge, Sabine Pass, Texas

The oriental latrine fly, Chrysomya megacephala (Fabricius), is one of four recently introduced Chrysomya species from the Australasian region with the potential for significant public health impacts and is spreading in North America (Greenberg 1988) and the continental U.S. (Wells 1991). The oriental latrine fly was first observed in Texas when a single male was collected in a trap near Kerrville. Whitworth (2006) described the species as rarely collected in the southern U.S., and Tenorio et al. (2003) noted adults are rarely observed in central Texas. Adults of the oriental latrine fly have been found in other parts of the Gulf Coast region of the U.S. (Tomberlin et al. 2001, Nelder et al. 2009), and this species is known to be established in Florida and Hawaii (Baumgartner 1993). Introductions of the oriental latrine fly and the hairy maggot blow fly, Chrysomya rufifacies (Macquart), were predicted to significantly reduce abundance of the native secondary screwworm, Cochliomyia macellaria (Fabricius), because of their long-standing evolutionary relationship (Wells and Kurahashi 1997) and apparent occupation of the same ecological niche (Baumgartner and Greenberg 1984, Wells and Greenberg 1992). While the hairy maggot blow fly has become well established in the continental U.S. (Baumgartner and Greenberg 1984) and continues to expand its distribution northward (Rosati and VanLaerhoven 2007), the oriental latrine fly seems to have been less successful and is restricted to the southern U.S. We observed the arrival and colonization of blow flies on a decaying domestic hog, Sus scrofa L., carcass (approximately 20 kg, frozen and defrosted) and two processed domestic chickens, Gallus gallus L. (approximately 2.2 kg each), in the McFaddin National Wildlife Refuge (Special Use Permit # 21521-09-011). The refuge is approximately 24 km south of Port Arthur in southeastern Texas, near the Louisiana border, and consists of 22,258 ha of coastal freshwater and brackish wetlands (Bossert 2009). The collection site was approximately 475 m inland from McFaddin Beach in an area recently burned by lightning-induced fire (<1 week prior) and in the path of Hurricane Ike (on 13 September 2008). During the afternoon (approximately 1500 hours) of 10 July 2009, we deployed the bait materials and made observations at deployment, approximately 1 hour before sunset (1900 hours) and from 0900 until 1300 hours on 11 July 2009 (mean temperature during the observation period = 29.5°C based on nearest National Weather Service from the Southeast Texas Regional Airport in Port Arthur, TX). ________________________ Diptera: Calliphoridae. Department of Entomology, Texas A&M University, College Station, TX 77843. Department of Biology, University of Windsor, Windsor, Ontario, Canada N9B3P4. College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.