Influence of biochar on succession of fungal communities during food waste composting.

This study aims to examine the effects of biochar on fungal dynamics during food waste composting. The different dosage of wheat straw biochar from 0 to 15% (0%, 2.5%, 5%, 7.5%, 10%, and 15%) were used as an additive to composting and examined for 42 days. The results showed that Ascomycota (94.64%) and Basidiomycota (5.36%) were the most dominant phyla. The most common fungal genera were Kluyveromyces (3.76%), Candida (5.34%), Trichoderma (2.30%), Fusarium (0.46%), Mycothermus-thermophilus (5.67%), Trametes (0.46%), and Trichosporon (3.38%). The average number of operational taxonomic units were 469, with the greatest abundance seen in the 7.5% and 10% treatments. Redundancy analysis revealed that different concentrations of biochar applied treatments have significantly distinct fungal communities. Additionally, correlation analyses of fungal interactions with environmental elements, performed through a heatmap, also indicate a distinct difference among the treatments. The study clearly demonstrates that 15% of biochar has a positive impact on fungal diversity and improves the food waste composting.

A comprehensive review on recent advancements in biodegradation and sustainable management of biopolymers.

Recent years have seen upsurge in plastic manufacturing and its utilization in various fields, such as, packaging, household goods, medical applications, and beauty products. Due to various adverse impacts imposed by synthetic plastics on the health of living well-being and the environment, the biopolymers have been emerged out an alternative. Although, the biopolymers such as polyhydroxyalkanoates (PHA) are entirely degradable. However, the other polymers, such as poly (lactic acid) (PLA) are only partially degradable and often not biosynthesized. Biodegradation of the polymers using microorganisms is considered an effective bioremediation approach. Biodegradation can be performed in aerobic and anaerobic environments. In this context, the present review discusses the biopolymer production, their persistence in the environment, aerobic biodegradation, anaerobic biodegradation, challenges associated with biodegradation and future perspectives. In addition, this review discusses the advancement in the technologies associated with biopolymer production, biodegradation, and their biodegradation standard in different environmental settings. Furthermore, differences in the degradation condition in the laboratory as well as on-site are discussed.

Effect of biochar addition on the dynamics of antibiotic resistant bacteria during the pig manure composting.

In present study, the taxonomic variation of antibiotic resistant bacteria (ARB) in pig manure (PM) composting with coconut shell biochar (CSB) and bamboo biochar (BB) addition was investigated. The experiment was divided into three treatments: T1 (as control or without biochar amendment), T2 was added 10% coconut shell biochar and T3 supplemented with 10% bamboo biochar. The initial feed stock were properly homogenized using a mechanical crusher. PM and wheat straw (WS) were mixed in a 5: 1 dry weight ratio to adjust the initial carbon/nitrogen ratio 25:1, bulk density to ~0.5 (kg/L) and ~60% moisture content, respectively. This experiment was lasted for 42 days. The results indicated the bacterial communities in the three treatments were more different in terms of relative abundance and diversity of dominant bacteria. The control group had the highest abundance of Kingdome bacteria. The changes in ARB was noticed by variation in the relative abundances of Actinobacteria, Proteobacteria, Firmicutes and Bacteroidota. At the end of composting (on day 42), the total RAs of ARB at the class, order, and family levels were considerably reduced in T2 and T3 by ~35.78-38.75%, 36.42-40.63% and 45.82-47.70%, respectively. But in T1 was decreased by 6.16-8.62%, 7.93-8.72% and 8.70-10.15%, as compared with the day 0 sample. However, the CSB was much more effective to reduce 55 to 60% of ARB than T3 or BB applied treatment has 40 to 42% ARB reduction, while control has certainly very less RAa of ARB reduction. Finally, the biochar amendment was significant approach to mitigate the total ARB abundance in compost and it's further used for organic farming purposes.

Effects of further composting black soldier fly larvae manure on toxic metals and resistant bacteria communities by cornstalk amendment.

Rapid composting by black soldier fly larvae (BSFL) may be insufficient to maturation and humification of composting and further composting is necessary. The purpose of this study was to explore cornstalk addition on toxic metals (Cu, Zn, Pb and Cd), toxic metals resistance bacterial (TMRB) destiny and their relationship with physicochemical factors during BSFL manure composting. High-throughput sequencing was performed by six treatments, namely T1 to T6, where T1 to T3 were BSFL manures from chicken, pig and dairy manure, respectively, and T4 to T6 were same manures and utilized cornstalk to adjust C/N to 25. The results showed that cornstalk amendment could enhance the toxic metals immobilization rate compared to control treatments in the ultimate product. TMRB indicated that the major potential hosts bacteria were Firmicutes, Bacteroidota, Proteobacteria, Acidobacteriota and Actinobacteriota, and the sum relative abundance were 63.33%, 90.62%, 83.62%, 69.38%, 50.66% and 90.52% in T1 to T6 at the end of composting. Bacteria diversity and heat map revealed composting micro-ecology with additive cornstalk to remarkably effect main resistant bacterial distribution via adjusting environmental factors and potential hosts bacterial. Finally, T5 treatment was able to greatly decrease the TMRB abundance, and improve the ability of composting and ultimate product quality.

Challenges and opportunities in bioremediation of micro-nano plastics: A review.

Rising level of micro-nano plastics (MNPs) in the natural ecosystem adversely impact the health of the environment and living organisms globally. MNPs enter in to the agro-ecosystem, flora and fauna, and human body via trophic transfer, ingestion and inhalation, resulting impediment in blood vessel, infertility, and abnormal behaviors. Therefore, it becomes indispensable to apply a novel approach to remediate MNPs from natural environment. Amongst the several prevailing technologies of MNPs remediation, microbial remediation is considered as greener technology. Microbial degradation of plastics is typically influenced by several biotic as well as abiotic factors, such as enzymatic mechanisms, substrates and co-substrates concentration, temperature, pH, oxidative stress, etc. Therefore, it is pivotal to recognize the key pathways adopted by microbes to utilize plastic fragments as a sole carbon source for the growth and development. In this context, this review critically discussed the role of various microbes and their enzymatic mechanisms involved in biodegradation of MNPs in wastewater (WW) stream, municipal sludge, municipal solid waste (MSW), and composting starting with biological and toxicological impacts of MNPs. Moreover, this review comprehensively discussed the deployment of various MNPs remediation technologies, such as enzymatic, advanced molecular, and bio-membrane technologies in fostering the bioremediation of MNPs from various environmental compartments along with their pros and cons and prospects for future research.

Current state of the art biotechnological strategies for conversion of watermelon wastes residues to biopolymers production: A review.

Poly-3-hydroxyalkanoates (PHA) are biodegradable and compostable polyesters. This review is aimed to provide a unique approach that can help think tanks to frame strategies aiming for clean technology by utilizing cutting edge biotechnological advances to convert fruit and vegetable waste to biopolymer. A PHA manufacturing method based on watermelon waste residue that does not require extensive pretreatment provides a more environmentally friendly and sustainable approach that utilizes an agricultural waste stream. Incorporating fruit processing industry by-products and water, and other resource conservation methods would not only make the manufacturing of microbial bio-plastics like PHA more eco-friendly, but will also help our sector transition to a bioeconomy with circular product streams. The final and most critical element of this review is an in-depth examination of the several hazards inherent in PHA manufacturing.

Evaluation of cornstalk as bulking agent on greenhouse gases emission and bacterial community during further composting.

The aim of current work was to explore the impact of Cornstalk (CS) on greenhouse gaseous emission and maturation during further composting and analyzed its impact on bacterial diversity. Three kinds of immature fertilizers were collected from chicken, pig and dairy manure namely T1, T2 and T3 as control, T4, T5 and T6 were added CS into T1 to T3 and adjusted C/N to 25 namely treatment. The results illustrated that gases (N2O, CH4 and NH3) emission of CS added treatments decreased by 6.39%-24.68%, 10.60%-23.23% and 13.00%-19.58%, respectively. But the CS amendment increased CO2 emission by 15.53%-30.81%. The mineralization of carbon and nitrogen was mainly correlated to Firmicutes, Actinobacteria, Proteobacteria and Bacteroidota, CS amendment increased abundance by 22.28%, 17.79%, 1.48% and 35.90%, respectively. The strategy of employing CS would be the most feasible approach for recycling of immature manure, considering its compost quality and environmental from farm.

Patterns of heavy metal resistant bacterial community succession influenced by biochar amendment during poultry manure composting.

The purpose of this study was to investigate the heavy metal resistant bacteria (HMRB) community succession and bacterial activity in poultry manure (PM) composting. Five different concentration of chicken manure biochar (CMB) at 0%, 2%, 4%, 6%, and 10% on a dry weight basis was applied with initial feedstock (poultry manure + wheat straw) and indicated with T1, T2, T3, T4, and T5. In addition, high-throughput sequencing, principal coordinate analysis, and correlation analysis were used to analyze the evolution of HMRB communities during composting. The study indicated that crucial phyla were Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes. The bacterial diversity in the CMB amendment treatment was higher than in the control treatment, and T4 treatment has the highest among all CMB applied treatments. Moreover, results from CCA indicated that T4 and T5 treatments quickly enters the high-temperature period which is maintained for 5 days, and is significantly positively correlated with Proteobacteria, and Actinobacteria. These findings offer insight into potential strategies to understand the succession of HMRBs during PM reuse. Overall, the above results show the addition of 6% biochar (T4) was potentially beneficial to enrich the abundance of bacterial community to improve composting environment quality and composting efficiency. In addition, effective to immobilized the heavy metals and HMRB in the end product.

Fungal dynamics during anaerobic digestion of sewage sludge combined with food waste at high organic loading rates in immersed membrane bioreactors.

In this study, the influence of distinct hydraulic retention times (HRT) and organic loading rates (OLRs) on fungal dynamics during food waste anaerobic digestion in immersed membrane-based bio-reactors (iMBR) were investigated. The organic loading rate 4-8 g VS/L/d (R1) and 6-10 g VS/L/d (R2) were set in two iMBR. T1 (1d), T2 (15d) and T3 (34d) samples collected from each bioreactor were analyzed fungal community by using 18s rDNA. In R2, T2 had the most abundant Ascomycota, Basidiomycota, Chytridiomycota and Mucoromycota. As for R1, T3 also had the richest Cryptomycota except above four kinds of fungi. Subsequently, the Principal Component Analysis (PCA) and Non-Metric Multi-Dimensional Scaling (NMDS) indicated that fungal diversity was varied among the all three phases (T1, T2, and T3) and each treatment (R1 and R2). Finally, the results showed that different OLRs and HRT have significantly influenced the fungal community.

Conversion food waste and sawdust into compost employing black soldier fly larvae (diptera: Stratiomyidae) under the optimized condition.

The increasing number of food waste (FW) had led to an urgent methods to recycle, black soldier fly larvae (BSFL) was a potential quick waste manager. To assess the impact of BSFL on conversion FW and sawdust into compost via the parameters of maturity, nutrient transformation and volatile fatty acids (VFAs). Meanwhile, the artificial of FW contained noodles, cabbages, rice and pork. FW and sawdust were employed by BSFL (6.5:0.5:1.2 ratio on fresh weight basis) as T1 and without BSFL called control (T2), while moisture content for FW and sawdust was 86.57% and 5.98%. Results illustrated that BSFL declined the composting time and only 9 d. Compared with initial mixture materials, T1 decreased organic matter, total kjeldahl nitrogen and VFAs from 97.41 to 85.96%, 23.01 to 17.77 g kg-1 and 3.25 to 1.69 g kg-1, respectively. However, T1 increased the total phosphorous and total potassium in 3.8 folds and 5 folds. The value of pH and EC reached at 4.27 and 1100 µS cm-1, and the germination index attained to 70.69%. In addition, redundancy analysis was used to analysis the correlation between factors under composting employed with different additive ratio of BSFL. Therefore, BSFL played a vital role in FW and sawdust recycling, especially reduced composting time and made the final separation of larvae and substrate easily, saving labor costs.

Can biochar regulate the fate of heavy metals (Cu and Zn) resistant bacteria community during the poultry manure composting?

In this study, the influence of coconut shell biochar addition (CSB) on heavy metals (Cu and Zn) resistance bacterial fate and there correlation with physicochemical parameters were evaluated during poultry manure composting. High-throughput sequencing was carried out on five treatments, namely T1-T5, where T2 to T5 were supplemented with 2.5%, 5%, 7.5% and 10% CSB, while T1 was used as control for the comparison. The results of HMRB indicated that the relative abundance of major potential bacterial host altered were Firmicutes (52.88-14.32%), Actinobacteria (35.20-4.99%), Bacteroidetes (0.05-15.07%) and Proteobacteria (0.01-20.28%) with elevated biochar concentration (0%-10%). Beta and alpha diversity as well as network analysis illustrated composting micro-environmental ecology with exogenous additive biochar to remarkably affect the dominant resistant bacterial community distribution by adjusting the interacting between driving environmental parameters with potential host bacterial in composting. Ultimately, the amendment of 7.5% CSB into poultry manure composting was able to significantly reduce the HMRB abundance, improve the composting efficiency and end product quality.

Manure pretreatments with black soldier fly Hermetia illucens L. (Diptera: Stratiomyidae): A study to reduce pathogen content.

This study aim was to investigate the influence of black soldier fly larvae (BSFL) Hermetia illucens L. (Diptera: Stratiomyidae) on pathogenic bacteria (PB) survival in the chicken manure (CM), pig manure (PM), cow manure (COM) and sewage sludge (SS) compost. Three kinds of manure [chicken (T2), pig (T4) and cow (T6)] and SS (T8) were inoculated with BSFL (1.2:7 ratio on fresh weight basis) and without BSFL (T1, T3, T5 and T7) was used as control and experiment lasted for 9 days. The results indicated that BSFL amendment 90-93% of PB abundances (RAs) was significantly mitigate in CM and COM (T2 and T6), and 86-88% in PM and SS compost. However, relatively greater abundance of PB was recorded in the T4 and T8 treatments. Most of the PB belong to Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes phylum and their community composition varied from phylum to species levels among the all treatments. The PB composition was significantly altered by BSFL amendment and also important role play to enhance in compost quality. Interestingly, Bacillus and Clostridium were significantly very less abundant present in BSFL applied treatments, but considerably higher population of these bacterial genus and its associated species were identifies from control or without BSFL applied treatments. Overall, without BSFL blended-all three kinds of manure-composts have comparatively greater PB abundance than with BSFL applied treatments, as the PB species Listeria_monocytogenes_FSL_R2-503, Staphylococcus_aureus_M0406, Bacillus_anthracis, Listeria_ivanovii, Staphylococcus_aureus_C0673, Salmonella Bacillus_cereus_VD115, Mycobacterium_tuberculosis_FJ05194 and Pseudomonas_aeruginosa has relatively greater RAs, followed by Bartonella_bacilliformis_Ver075; Bordetella_pertussis_2356847; Brucella_melitensis_ADMAS-G1; Klebsiella_pneumoniae_LCT-KP182 and Corynebacterium_jeikeium_K411 respectively. Thus, chicken manure composting with BSFL addition is efficient technology for the organic waste recycling and conversion of sanitized matured compost with significantly less abundance of pathogenic bacteria.

Effect of red kaolin on the diversity of functional genes based on Kyoto Encyclopedia of Genes and Genomes pathways during chicken manure composting.

The transcription and expression of functional genes governed the biotransformation of nutrients during composting. In this study, the diversities of functional genes were investigated in 50 days chicken manure composting through six treatments amended with different dosage of red kaolin. Results showed that based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation, Metabolism possessed largest proportion and richest genes number among six pathways, of which carbohydrate metabolism (81007) were significantly greater than others; while Human Disease and Organismal Systems were relatively lower. Meanwhile, the addition of red kaolin has an important impact on dynamics of KEGG genes, the relative abundance of detected genes were distinctively different in all treatments. Similarity analysis also showed the varying influence of different proportion of red kaolin on functional genes during chicken manure composting. In conclusion, application of red kaolin in chicken manure composting effectively improved the relative abundance of functional genes.

Evaluation of biochar amendment on heavy metal resistant bacteria abundance in biosolids compost.

The present investigation was design to evaluate the impact of different dosages of biochar on heavy metal resistant bacterial (HMRB) dynamic in biosolid (BS) compost. The bacterial abundance map was reveals that all the samples have 35 prominent genera and showed significant alteration of HMRB among the all biochar applied treatment. The main phyla identify in each treatments were Proteobacteria, Firmicutes and Chloroflexi, however, Pseudomonas, T78, Acinetobacter and Urebacillus were most abundant genera in all the treatment. The visualization of HMRB bio-diversity by bioinformatic tools and krona were clearly indicated a considerable difference in classification tree complexes and network analysis among the all biochar added treatments. Thus, in present study was found that HMRB like Paracoccus, Planomicrobium, Devosia and Agrobacterium viable hyper-thermo tolerant in BS compost. In addition, heat map analysis also confirmed that Proteobacteria, Firmicutes and Chloroflexi have significant correlation with physicochemical parameters.

Effect of fine coal gasification slag on improvement of bacterial diversity community during the pig manure composting.

In present study, evaluate the effect of fine coal gasification slag (FCGS) as additive on abundance of bacterial diversity during pig manure composting. The six different dosages of FCGS 0% (T1), 2% (T2), 4% (T3), 6% (T4), 8% (T5) and 10% (T6) (dry weight basis) were mixed with original raw materials for 42 days an aerobic composting. The results indicated that FCGS adopted could affect the succession of bacterial diversity in different ways. Among all treatments, Firmicutes, Proteobacteria, Tenericutes, unidentified_Bacteria, and Actinobacteria were the highest abundance in weighted unifrac distance but Firmicutes; Proteobacteria, Actinobacteria, Bacteroidetes, and Spirochaetes were main bacteria in unweighted unifrac distance. The ß-diversity and principal component analysis indicated a significant difference in bacterial diversity in all treatments which T4 obtained difference obviously. Therefore, the results showed that T4 was a potential candidate to enhance significantly abundance of bacterial community in PM compost.

Influence of bamboo biochar on mitigating greenhouse gas emissions and nitrogen loss during poultry manure composting.

The effectiveness of specific concentrations of bamboo biochar (BB) on nutrient conservation based on gaseous emissions during poultry manure composting was investigated. The results indicate that the total carbon and nitrogen losses were significantly reduced with elevated of biochar from 542.8 to 148.9% and 53.5 to 12.6% (correspondingly with an additive of 0%, 2%, 4%, 6% and 8% to 10% BB dry weight based). The primary contributor was CO2 and NH3 losses (542.3-148.8% and 47.8-10.81%). The enzyme activities related to carbon and nitrogen metabolism indicated a positive and significantly enhanced with high concentration biochar amended composting. Simultaneously, the alteration of total organic carbon and total Kjeldahl nitrogen as well as maturity indexes during ultimate compost also confirmed a high quality product under higher content biochar amended composting. Carbon and nitrogen were best preserved with 10%BB and produced a superior final product. The analysis of a network and heat map illustrated the correlation of gaseous and physicochemical elements as well as enzyme activities, with an intersection of 68.81%.

Relevance of biochar to influence the bacterial succession during pig manure composting.

The influence of pig manure biochar amendment (PMBA) during the pig manure (PM) and wheat straw (WS) composting was evaluated. Five concentration of PMBA (0%, 2%, 4%, 6% and10%) were applied to explore the bacterial distributions in PM compost by 16SDNA amplicons sequencing. The results showed that the addition of 6% PMBA could significantly enhanced the bacterial community abundance compared with other composts, while control has relative less bacterial population (332 OTU). The visualization of phylogenetic tree and krona demonstrated the distinctive distribution of each composts, suggested that biochar dosages have an influence on bacterial communities' variation during co-composting. Beta-diversity of distance matrix heat-map and principal component analysis confirmed that bacterial communities were considerably correlated with increasing PMBA. Redundancy also confirmed the similarity and discrepancy among all treatments and environmental factors. This work considered as the potential of PMBA as a booster in composting, where T4 has most plentiful bacterial community and diversity.

Effects of black soldier fly larvae (Diptera: Stratiomyidae) on food waste and sewage sludge composting.

With the rapid development of the economy and population, the improvement of life level, enormous organic wastes have been generated. Black soldier fly larvae (BSFL) treatment is an attractive management method as it provides a strategy for waste treatment while also generate biofertilizers. The aim of this study was to evaluate the BSFL processing residue quality through the physical and chemical parameters. The sewage sludge (T1) and food waste (T2) were employed with BSFL (7:1.2 ration on fresh weight basis) and without BSFL T3 and T4 was marked control and composted for 9 days. The results showed that the BSFL composting reduced the organic matter by 14.51-21.98% and the accumulation of volatile fatty acids by 10.12-28.50%. While BSFL composting greatly increased total kjeldahl nitrogen by 23.15% compared with T4, T1 remained essentially unchanged. The additive of BSFL was significantly increased the total phosphorous and potassium in T2, but T1 remained stable compared with control. These results showed that the BSFL could improve the quality of end product and promote the food waste degradation. The current study indicates that the BSFL management provides an environmentally relevant alternative with very convenience in food waste. Further research should focus on residue sanitation.

Emerging applications of biochar: Improving pig manure composting and attenuation of heavy metal mobility in mature compost.

This study evaluated the effect of integrated bacterial culture and biochar on heavy metal (HM) stabilization and microbial activity during pig manure composting. High-throughput sequencing was carried out on six treatments, namely T1-T6, where T2 was single application of bacteria culture (C), T3 and T5 were supplemented with 12 % wood (WB) and wheat-straw biochar (WSB), respectively, and T4 and T6 had a combination of bacterial consortium mixed with biochar (12 % WB and 12 % WSB, respectively). T1 was used as control for the comparison. The results show that the populations of bacterial phyla were significantly greater in T6 and T4. The predominate phylum were Proteobacteria (56.22 %), Bacteroidetes (35.40 %), and Firmicutes (8.38 %), and the dominant genera were Marinimicrobium (53.14 %), Moheibacter (35.22 %), and Erysipelothrix (5.02 %). Additionally, the correlation analysis revealed the significance of T6, as the interaction of biochar and bacterial culture influenced the HM adsorption efficiency and microbial dynamics during composting. Overall, the integrated bacterial culture and biochar application promoted the immobilization of HMs (Cu and Zn) owing to improved adsorption, and enhanced the abundance and selectivity of the bacterial community to promote degradation and improving the safety and quality of the final compost product.

Resource recovery and circular economy from organic solid waste using aerobic and anaerobic digestion technologies.

With the inevitable rise in human population, resource recovery from waste stream is becoming important for a sustainable economy, conservation of the ecosystem as well as for reducing the dependence on the finite natural resources. In this regard, a bio-based circular economy considers organic wastes and residues as potential resources that can be utilized to supply chemicals, nutrients, and fuels needed by mankind. This review explored the role of aerobic and anaerobic digestion technologies for the advancement of a bio-based circular society. The developed routes within the anaerobic digestion domain, such as the production of biogas and other high-value chemicals (volatile fatty acids) were discussed. The potential to recover important nutrients, such as nitrogen through composting, was also addressed. An emphasis was made on the innovative models for improved economics and process performance, which include co-digestion of various organic solid wastes, recovery of multiple bio-products, and integrated bioprocesses.