Larval biomass production from the co-digestion of mushroom root waste and soybean curd residues by black soldier �y larvae (Hermetia illucens L.)

Black soldier �y larvae (BSFL) are progressively being used as a sustainable waste management solution. They are high in protein and other essential nutrients, making them an ideal food source for livestock, poultry, and �sh. Pure mushroom root waste (MRW) has been shown in the past to have a poor conversion e�ciency, taking much more time than regular arti�cial diet in prior laboratory studies. Therefore, the nutrient rich soybean curd residues (SCR) was mixed with MRW, the combination of SCR and MRW increased the diversity of the gut microbiota, which was favorable for the development and growth of the larvae. As compared to all of the other feed combination groups, the longest developing period of BSFL in (M1) pure MRW was 31.1 days. When compared to the M1 and M7 groups, the mixture groups achieved the highest reductions in dry mass (49.7%), bioconversion rate (5.9%), protein content (46.0%) and lipid content (25.2%). Based on the different performance parameters of different mixtures of MRW and SCR, Lipid and protein content and FCR in BSFL were the essential parameters to evaluate the conversion e�ciency of BSFL. SEM pictures and FT-IR spectra indicated that the group M4 MRW structures altered to hollow and �ber excision, which improved the co-conversion mixture. BSFL (M4) can co-convert �ber rich MRW with SCR.


Introduction
The capacity to effectively manage waste is essential to the long-term health of the ecosystem (Ji-bin et al. 2020; Rehman et al. 2022; Singh et al. 2022).The conventional method of managing organic waste, which involves activities such as burning agro-industrial waste, may result in the emission of dangerous pollutants into the air (Rehman et al. 2022; Saravanan et al. 2022;Soomro et al. 2021).On the other hand, disposing of it in land lls can be ine cient use of space and can pollute groundwater (Barati et al 2022).
Moreover, the burning and land ll disposal has a number of disadvantages including the release of unpleasant odors, the consumption of valuable space by waste, the proliferation of greenhouse gas emissions, the growth of pathogenic microorganisms, and environmental contamination (Barati et al. 2022;Hoang et al. 2022).To reduce the environmental impact of agro-industrial waste, it is important to nd ways to reuse or recycle it.The global mushroom cultivation market was worth $16.37 billion in 2019, and it is anticipated that it will reach $26.09 billion by 2027, expanding at a compound annual growth rate (CAGR) of 6.0% throughout the time of the projection Klaus and Wan-Mohtar (2022).A mushroom's ranking among heterotrophic organisms in the vegetable kingdom Klaus and Wan-Mohtar (2022).Mushrooms can't produce oxygen via photosynthesis as green plants can.Mushrooms are grown using a variety of waste items such as straw, horse manure, gypsum, and wastewater (Maity et al. 2021).
Due to its widespread use and potential health bene ts, golden needle mushrooms are a component of the mushroom market that is expected to see high demand.Mass production has occurred in the world's leading mushroom-producing nations, including Japan, Germany, China, the United States, and Poland (Atila 2019; Postemsky et al. 2022;Tieu et al. 2022).
The golden needle mushroom (GNM, also known as Flammulina velutipes) is the species of mushroom that is farmed the most often all over the globe (Cai et al. 2019).Only the part of the mushroom that is edible is harvested, and the substrate that is left behind contains remnants of edible mushrooms as well as roughly 75-85% nutrients that were not used (Cai et al. 2019).The greater the quantity of GNM that is produced, the greater the quantity of its associated production waste, which almost doubles in yield and, along with residues, becomes an enormous burden that drives up the cost of treatment (Dong et al. 2021;Shrikhandia et al. 2022).According to former investigations, the production of lignocellulose biomass on the surface of the globe has increased to more than 200 ×10 9 tons per year (Lu et al. 2021;Zhao et al. 2020).The vast bulk of this organic waste is inedible in its current state and contributes to concerns of environmental contamination (Ali et al. 2020).In general, harvesting one kilograms of edible fungus results in the production of 3.25 kilograms of substrate leftovers (Li et al. 2021).As a result, substrate leftovers are an example of nutrient-rich organic waste that might be put to another useful use (Cai et al. 2019; Li et al. 2021).Mushrooms are really useful from a nutritional aspect.They are cholesterol-free, low in fat, rich in protein (including all the necessary amino acids), and high in dietary ber (Cai et al. 2019).It is anticipated that the current upward trend in mushroom output will continue into the foreseeable future.Therefore, there is an immediate necessity alternative technological solution for the management of GNM.
White to yellow, brous, and gluten-free, soybean curd residues (SCR) are the insoluble component of soybean seeds that remains after the aqueous portion is drained during the manufacturing of tofu and soy milk.Okara, douzha, and tofuzha are Chinese names for SCR; tofukasu is Japanese; and bejee is Korean (Soomro et  ).Using agro-industrial byproducts as a food supply is one way food scientists are trying to lessen the ecological footprint of SCR production (Li et al. 2012(Li et al. , 2019)).Because of this, there has to be a more sustainable approach to dealing with used straws.
Black soldier y (Hermetia illucens) larvae, often known as BSFL, are exceptional insects for the bioconversion of organic waste since they can convert both separate and combined waste (Somroo et al. 2019;Ji-bin et al. 2020;Rehman et al. 2022).The treatment procedure using BSFL had been applied to many different forms of manure, food, vegetable waste and crop residues, which could create a biomass of protein, fat, and other byproducts, such as organic fertilizer, chitin, antibacterial peptide, and biodiesel (Liu et Liu et al. 2017).It's possible that this developing procedure will satisfy the co-digestion of mushroom root with highly nutritious SCR organic waste.During this research, an innovative bioconversion and composting method for MRW that makes use of SCR and BSFL to generate enriched biomass was developed.In addition, the nutritional qualities of the SCR mixes that were combined with MRW were evaluated, as well as their impacts on the growth of the larvae, the reduction of waste, the conversion of material, and the consumption of nutrients in the BSFL treatment system.

Materials and methods
The experiment was carried out in the greenhouse of the State Key Laboratory of Agricultural Microbiology at Huazhong Agricultural University (HZAU) of Wuhan, China.

Source and development of BSFL
A colony of black soldier ies known as Hermetia illucens, the Wuhan strain, has been cultivated for the last 14 years at the institution's State Key Laboratory of Agricultural Microbiology of HZAU, Wuhan (Soomro et al. 2021;Zhou et al. 2013).Before being utilized in the tests, BSFL were given MWR and SCR and y larva from a modi ed arti cial diet for a period of six days (the modi ed arti cial diet consisted of 75 g of bran, 75 g of maize our, and 350 g of water) (Ma et al. 2018).

Mushroom root waste and soybean curd residues: source and physicochemical properties
The fresh mushroom root waste (MRW) was acquired from Ruyi Edible Mushroom Co., Ltd.situated in Hutong Street, District Xihu, Wuhan City, Hubei Province, China.The Soybean curd residues (SCR) was gathered from the cafeteria of HZAU, Wuhan, China.MRW and SCR were put down in a preservation room at 4°C.Three 200 g samples were randomly selected before the experiment, and analyzed their nutritional parameters by the Shanghai Supervision and Testing Center for Feed Quality corresponding to the guideline coded as GB/T 6434 − 2006, GB/T 13080 − 2004, GB/T 18246 − 2000, and GB/T 13082 − 1991, Standardization Administration of the P R China.The physicochemical characteristics are mentioned in (Table 1).The water content of SCR and MRW was quanti ed by gaining 10 g samples of each and put them into three glass dishes.Then, the material samples were dried at 60°C for the determination of dry matter and water content.The water content for MRW, SCR and arti cial feed was 15.3%, 83.4% and 7.0% respectively.
On a dry matter basis, 400 6-day-old larvae were injected into 200 g of feed (Table 2).The study was carried out in a greenhouse, with the temperature set at 27°C and the humidity between 60% and 70%.The effectiveness of BSFL in feeding MRW and SCR was evaluated by tracking BSFL development throughout the transformation.When the rst pre-pupae emerged in each of the duplicate containers, the experiment was stopped.During the harvest, sterile forceps were used to physically separate the larvae from the leftover debris.Later than cleaned with puri ed water, the larvae were dehydrated at 60°C for two days before being inactivated at 105°C for 5 min.We calculated the total amount of dry matter consumed by each treatment group as detailed above.

Heavy metals
The concentrations of heavy metals, being copper, zinc, cadmium, mercury, lead, and arsenic (Cu, Zn, Cd, Hg, Pb, and As) in BSFL were measured by Atomic Absorption Spectrophotometer (Perkin Elmer 403) at wavelengths particular to each metal according to the technique stated by Don-Pedro et al. ( 2004).

Scanning electron microscopy (SEM)
The bers of MRW and SCR was determined at an accelerating voltage of 3.0 kV using SEM (HITACHI S-4800 Scanning Electron Microscope, Japan).The dried samples were mounted on double-sided tape placed on aluminum stubs.A golden thin layer (15 nm, 10 min) was sputtered to reduce the electron altering effects on the mounted samples.Lastly, the gold-coated samples were examined with SEM as previously described method by (Rehman et al. 2019, 2017a, b).

Fourier transform-infrared spectroscopy
To describe how MRW and SCR mixes changed chemically during BSFL treatment, we rst isolated the functional groups in the biomass and then compared them to M1.According to a previously documented approach, FTIR spectroscopy (Nicolet iS50, Thermo Scienti c, USA) was used to perform the characterization (Rehman et al. 2019).In order to create uniform pellets at 1 Mpa, we dried the samples in an oven, crushed them with KBr (spectral grade), mixed them well in an agated mortar, and then compressed them.The Nicolet iS50 FT-IR spectrometer was used to capture the IR spectra at a frequency of 0.5 cm/s (Rehman et al. 2019).

Statistical analysis
The statistical analysis of the obtained results was performed by SPSS 16.0 (SPSS Inc., Chicago, IL, USA).One-way analysis of variance (ANOVA) was used to analyze the experimental results.The post hoc Tukey's HSD test was used to compare and reveal signi cant differences among the means of the different.By comparing the results, p < 0.05 was considered signi cant.

Results
3.1 Survival rate, developmental time, and fresh and dry weight of BSFL Every combination of MRW and SCR was deemed adequate for BSFL's growth, maintenance, and output.
The survival rate was lowest for pure MRW (M1), at 86.2%, and highest for pure SCR (M4), at 96.9%.Accumulation of pure SCR shortened the duration of BSFL development from its longest point (31.1 days) in pure MRW to its lowest point (22.0 and 21.5 days) in M4 and M5, respectively.Fresh BSFL yield was lowest (24.1 g) in M1and dried BSFL yield was greatest (60.6 g) in M5, whereas yield rose across the board (Table 3).(Average ± SD; n = 3).Average values followed by the similar alphabets within a column signi cantly do not differ.

Nutritional composition of BSFL
Protein and lipids make up the majority of an insect's make-up.M4 (45.7%) and M5 (46.0%) had signi cantly greater protein levels than the other feeding combination groups.When compared to pure MRW and other feeding combinations, both M4 (25.2%) and M5 (24.3%) had considerably larger lipid levels.M1 and M2 both had ash concentrations of 6.0%, which was lower than M5 but greater than the other feeding combinations (Table 5).(Average ± SD; n = 3).Average values followed by the similar alphabets within a column signi cantly do not differ.

Essential and nonessential amino acids in BSFL
The amino acid content of BSFL protein was analyzed in order to determine its nutritional pro le.This was done by growing BSFL on optimal ratios of M4.According to the ndings, the levels of histidine (3.6%), methionine (2.7%), phenylalanine (3.1%), and threonine (3.8%) were signi cantly higher in group M4 when compared to the control group and the WHO/FAO/UNU norm.In addition, the levels of the nonessential amino acids aspartic acid (4.5%) and glycine (2.7%) were found to be greater in group M4 than they were in the level seen in the control group (Table 6).(Average ± SD; n = 3).Average values followed by the similar alphabets within a column signi cantly do not differ.

Heavy metals in BSFL
It noticed that there was a signi cant differences in the levels of heavy metals across the different groups (Table 8).The concentrations of copper (Cu), lead (Pb), and arsenic (As) did not vary signi cantly from one another signi cantly.Both groups had concentrations of cadmium (Cd) and mercury (Hg) that were below 0.01 parts per million.Only the zinc (Zn) concentration in the control group was greater than that of M4, and no other group had a concentration higher than M4.

Fiber surface pro le changes in MRW and SCR during BSFL co-conversion
The ber structures of MRW, SCR, and their co-conversion feeding mixes were compared before and after BSFL applications using scanning electron microscopy.Surface pro le analysis included a 3500-fold ampli cation of both unaltered and treated MRW and co-conversion mixture samples (Fig. 2. M 0 1-M6).
The predigested MRW and SCR showed a more compact, rigid, and consolidated morphological structure (Fig. 2. M 0 1 and M 0 6).When BSFL nished digesting the buildings, they were left hollow (Fig. 2. M1, M2, M3, M4, M5, and M6). Figure 2 presents that when the compact surface structure of ber was subjected to various co-conversion mixes (M4, M5) during hydrolysis, it displayed more cracked, splited, and holes than it did when subjected to other feeding combinations or the control group.

Fourier transform infrared spectroscopy (FT-IR)
The FT-IR spectra of various feeding combinations were analyzed in the residues that were treated with BSLF, and the results were compared with M1's results (Fig. 3).While compared to the M1 (control), the band at 2352 cm − 1 that is attributable to the axil distortions of the stretched C = O bonds was found in group M4 and M5, but not in the control M1.However, it's possible that the partial removal of ber is to blame for the lower absorption at 1025 and 674 cm − 1 .When BSFL formed on the feed mixture, there were noticeable alterations in the ber.

Discussion
our knowledge, this is the rst comprehensive look into SCR's effects on various MRW combinations.
Together, MRW and SCR are utilized to investigate the impact that BSFL research and development may have on organic waste management.The impacts of MRW co-conversion with SCR were also studied.
The ndings showed that when compared to pure MRW and the control feed, the blends of MRW with SCR improved all the performance metrics and life history features of the BSFL.When compared to using just MRW, the accelerating effectiveness of BSFL was improved when varied ratios of SCR were added to the feed mixes (M2-M5), and the rates of dry mass reduction and bioconversion were also raised.In the current investigation, dry mass was reduced by 39%-51%.Similarly high rates of recycling nutrients were found in chicken feed and swine manure (23%-44% and 39%), (Diener et al. 2009), and a mixture of chicken and dairy manure (43%-55%) (Rehman et al. 2019, 2017b).Our 3.5%-6.6%bioconversion rate is comparable to the rates seen in municipal organic waste (5.7%) and dairy manure (6.3%) (Diener et  .We noticed all heavy metal levels in BSFL to be safe for human consumption.(Table 8).
For morphological structure analysis, SEM was used on MRW feeding mixes, pure MRW, and SCR (control).Compared to the micrograph of BSFL digestion, pure MRW and SCR bres were strongly bound with a compressed and robust surface (Fig. 2).In varied feed mixes MRW supplemented with SCR, BSFL transformed the rmed surface structure to porous and cracked (Fig. Using FT-IR, we compared the chemical structures of the bres in the mixes to M1 to further study the impacts of BSFL co-conversion on bre content breakdown (Fig. 3).The stretching of C-deformation and symmetric aromatic C-H deformation groups caused the distinctive FT-IR bands at 1025 cm − 1 .Aromatic C-H deformation affects lignin, cellulose and hemicellulose (Rehman et al. 2019).

Conclusion
The co-conversion of various feed mixes ratios of ber-rich MRW with SCR by BSFL found that a ratio of MRW:SCR equal to 40:60 was the most acceptable (M4).It speeds up the conversion process while also increased the e ciency of the conversion.The environmentally problematical MRW with high ber content was di cult to degrade in the environment.The addition of different percentages of SCR with MRW increased all the performance parameters and nutritional value in BSFL.When MRW was mixed with SCR, the developmental time of BSFL shortened.The highest dry mass reduction, bioconversion rate, protein content, and lipid content in different mixture groups were obtained compared with that in pure MRW group and arti cial feed group.Moreover, no signi cant difference in lipid content, protein content, and FCR was observed between M4 and M5.Our main target was to utilize more MRW from the environment; hence, we preferred M4 for further nutritional and safety investigations.The amino acid and fatty acid spectra of BSFL were higher in M4 compared the control groups.Moreover, the reported values of amino acids in BSFL develop on M4 were compared with the WHO/FAO/UNU standards for human consumption and with sh and soybean meal.Furthermore, the analyzed heavy metals levels in BSFL were lower the MPL and within the safety intake level in human and animal nutrition when compared with WHO/FAO and China national security standard of food and feed.Hence, the growth of BSF larvae found on MRW 40% and SCR 60% (M4) are more utilize by BSFL.

2 . 5
Survival rate (%) = [Larvae's number at the ends of the experiment / Larvae's number at the initiation of experiment] × 100% (1) Development time (days) = Age of larvae at the ends of the experiment (days) -Age of larvae at the initiation of the experiment (days) (2) Bioconversion rate = [total larval biomass (g) / feed added (g)] × 100% (3) FCR (g/g) = feed ingestion (g) / earned mass (g) (4) Dry mass reduction (%) = [Weight of feed at the initiation of the experiment (g) -Weight of residue at the ends of the experiment (g)/Weight of feed at the initiation of the experiment (g)] ×100% (5) Chemical analyses 2.6 Lipid and fatty acid pro le The previous research calculated the lipid content of BSFL from 2.0 g of dried BSFL using petroleum ether and Soxhlet extraction techniques (Somroo et al. 2019; Rehman et al. 2018; Wang et al. 2017).Comparing the weight of the sample before and after extraction allowed us to measure the lipid content.Liu et al. (2017) standard's technique (GB/T 17376 − 2008) was used to determine the fatty acid (FA) pro le of BSFL.

2. 7
Protein and amino acid pro le By using the same method used to calculate crude protein content of BSFL by multiplying the nitrogen content of dry larvae by a conversion factor of 6.25, as indicated by(Somroo et al. 2019;Chakravorty et al. 2016).Total Kjeldahl nitrogen (TKN) was used as the nitrogen standard using the standard technique designated as (NY 525-2011) by the Standardization Administration of the P.R of China, the TKN, TP (total phosphorus), and TOC (total organic carbon) of the residual samples were calculated (Rehman et al. 2017a).High-performance liquid chromatography (HPLC, Agilent 1100) being used to measure the total amino acid content of captured BSF larvae in accordance with the referenced standard technique (GGB/T 5009.124-2003)(Somroo et al. 2019;Liu et al. 2017).

Table 2
Number of larvae, percentage of mushroom root waste and soybean curd residues in different feeding mixtures (Somroo et al. 2019;Rehman et al. 2019l biomass (total weight of fresh and dried larvae weight per container), bioconversion rate, feed conversion ratio (FCR), and waste reduction were established as processing metrics for BSFL(Somroo et al. 2019;Rehman et al. 2019 Rehman et al.  , 2017a, b), b).

Table 3
Survival rate (%), developmental time (days), and fresh and dry larval biomass weight (g) of BSFL reared on different mixtures of MRW, SCR, and arti cial feed

Table 4
Dry mass reduction rate, bioconversion rate, and FCR of BSFL reared on different mixtures of MRW, and SCR, and arti cial feed

Table 5
Nutritional components of BSFL reared on MRW, SCR and arti cial feed

Table 6
Essential amino acid composition of in BSFL reared on M4 (MRW 40% and 60% SCR) and comparison with WHO/FAO standard (mg/100 g)

Table 7
Fatty acids composition of BSFL reared on M4 (MRW 40% and 60% SCR; mg/100 g) (Average ± SD; n = 3).Average values followed by the similar alphabets within a column signi cantly do not differ.

Table 8
Heavy metal (mg/ Kg) concentrations in BSFL reared on M4 (MRW 40% and 60% SCR).Nitrogen reduction percentages increased to as high as 50.5% in group M4 and 51.7% in group M5 thanks to the use of varying SCR to MRW ratios.
Data on nutrients and rate of reduction are shown in Fig.1.decrease was highest in M6, at 71.7%, and lowest in M1.Compared to the other feeding combinations and the control, M4 (62.5%) and M5 (62.6%) had the highest carbon reduction rates.Carbon rates in M1 were found to be rather low (50.7%).M6 had a high nitrogen reduction rate (55.7%), whereas M1 had a low one (38%).
(Bava et al. 2019;Lee et al. 2008;Raksasat et al. 2020e current study's BSFL survival rate and development time on MRW and SCR were low (Ji-bin et al. 2020; Liu et al. 2022; Rehman et al. 2022; Somroo et al. 2019).High survival rates and short maturation durations are seen in the various co-conversion mixes.The survival rate ranged from 86-96% in the existing experiment, which was comparable to the 93% that was testi ed for fermented maize straw diet(Gao etal.2019), the 87% that was stated for cow manure Broekhoven et al. 2015; Diener et al. 2009; Holmes, 2010; Rehman et al. 2022, 2017b; Somroo et al. 2019) As a result of MRW being co-converted with SCR, BSFL output weights went up.Similar to the ndings that co-digestions of multiple feeds boosted the yield (Rehman et al. 2022, 2019; Wang et al. 2021), wefound that MRW mixed with SCR signi cantly increased BSFL production across all treatments (fresh and dried larval weights).Moreover, the ndings of the current research are consistent with those of the previous, demonstrating that various co-digestion mixes improve buffer capacity, nutritional balance, and yield(Gobbi et al. 2013; Rehman et al. 2017a, b).Insect productivity and survival are in uenced by the quality of their meal(Bava et al. 2019;Lee et al. 2008;Raksasat et al. 2020).MRW has a higher buffering capacity due to its excessive ber and cellulose content, while SCR is more readily biodegradable, has a more environmentally acceptable composition, and can be acidi ed with less effort (Rehman0 et al. 2022, (D. Oonincx et al. 2015; D. G. A. B. Oonincx et al. 2015), the 93% that was stated for hen feed (Ma et al. 2018; Wang et al. 2017), and the 91%-99% that was reported for dairy manure and SCR (Somroo et al. 2019; Rehman et al. 2017a).Several elements, including availability and feed mix, old and new manure, humidity and temperature, are what in uence the performance measures, such as survival ratio and growth time ( Liland et al. 201708)ehman et al. 2019 comparison to previous studies, the present research found an FCR of 7.8-11.1% for co-digestion mixtures of dairy manure and SCR and chicken manure and dairy manure(Somroo et al. 2019;Rehman et al. 2019 Rehman et al.  , 2017a, b), b), and 9.6-10.2%forswinemanure(Sheppardetal.1994).Dry mass reduction and bioconversion are two areas where codigestion feeding mixes of MRW and SCR might be helpful (Table4).In addition,Zhou et al. (2013)found that temperature change may account for the life cycle features, waste reduction data, and phenotypic variability across BSF strains seen in BSF larvae.)alsoacquiredahighrate of carbon eduction in SCR, however they got 71.9%.Co-digestion mixes M4 and M5 had carbon reduction rates of 62.5% and 62.6%, respectively.The carbon content of compost decreases and the rate of reduction varies throughout vermicomposting, according to research by(Lazcano et al. 2008), and(Nair et al. 2006).Insect carbon loss occurs mostly as a result of the metabolic processes of associated microbes in the digestive tract (Rehman et al. 2019, 2017a, b).Carbon reduction is dynamic, but it is aided by BSFL activity in the system (Rehman et al. 2017a).The breakdown and homogenization of insect diets by muscular activity that increase surface area for microbial colonization leads to a drop in total organic carbon (TOC) (Rehman et al. 2022, 2017a).Moreover, the MRW has 1.5% and 3.5% total nitrogen (TN) shown in (Table1).Previous investigations on MRW (2.7%, Cai et al., 2017) and dairy manure and SCR (3.3%) (Somroo et al. 2019; Rehman et al. 2017a, The insects that can be sustainably nurtured on organic side streams could produce suitable alternative sources of animal protein and fat.However, the amounts of protein and lipids vary widely and depend on the type of diet.(Liuetal.2017;Somrooet al. 2019; Rehman et al. 2022).The protein contents in M4 and M5 increased up to 46.0% by assisting SCR with MRW.The outcomes of the existing study are similar with the preceding result for chicken feed (47.0%) reported by (Bosch et al. 2014; Nguyen et al. 2015; Oonincx et al. 2015b).In the range of 16.7-29.1%,BSFLlipidcontentwasfound.This research found tha BSFL raised on pure MRW had a lipid content of 16.7%, which is consistent with the results of the preceding work by the same authors (Cai et al. 2019) on the same substrate.The lipid amounts in both groups went raised when SCR was added to the MRW.With M4, the lipid percentage jumped from 16.7-25.2%.While a larva's body composition is determined by the quality and amount of the food it consumes, similar ndings were observed in swine dung and other by-products (St-Hilaire et al. 2007b; Nguyen et al. 2015; Gobbi 2012; Nguyen et al. 2015).Renna 2017b).BSFL grown on processed wheat, mixed middling, and broiler starting diet has 3.8% threonine (Liland et al. 2017; Tschirner and Simon 2015; Bosch et al. 2014).Due to its high amino acidand calcium content and palatability, BSFL are used to feed chickens, sh, and pigs.Thus, BSFL are being studied as human and pet dietary ingredients.The histidine, methionine, phenylalanine, andLiland et al. 2017).These essential fatty acids are involved for long-chain polyunsaturated fatty acid production and brain, cell membrane and nerve impulse activity.Fatty acids help carry atmospheric oxygen to plasma, synthesize hemoglobin, and divide cells(Marineli etal.2012).Heavy metal deposition in agricultural products is a global health problem.Heavy metals are harmful even at low amounts because they accumulate (Elliott et al. 2017; Murtaugh et al. 2017).The heavy metals in M4 (Cu and Cd) are in line with (SCR and AF; Cu 0.06 and 0.08, Cd 0.04 and 0.02; Somroo et.al 2019).Heavy metals could transfer from food into the BSFL and from impure soil into detritivorous animals (Diener et al. 2015; Adeniyi et al. 2003).Yellow mealworm (Tenebrio molitor) and BSFL also absorbs bio-waste cadmium, lead, mercury, zinc, and arsenic, which may exceed animal feed requirements.(Diener 2015; Gao 2017; Purschke 2017; van Der Fels-Klerx 2017).We examined heavy metal concentrations in BSFL and compared them to two major food and feed safety standards (WHO/FAO, 2007; National Hygienic Standard for Food in China) Sealey et al. 2011)7;e et al. 2017).M4 has 1Renna et al. 2017b (C16:0), equivalent to BSFL raised on wheat seaweed (16.6%), bread (12-20%), and cow manure (16.1%) stated by(Liland and al. 2017;   Oonincx et al. 2015;Renna et al. 2017b).Palmitoleic acid (C16:1n7) was 5.2%, like cow manure-derived BSFL (5.3%;Sealey et al. 2011).In this research, BSFL raised on bread and cow and swine dung have 3.0% stearic acid (C18:0).Oleic acid (C18:1n9) concentration was 17.3%, similar to wheat seaweed-derived BSFL (