Recent trends in bioethanol production from food processing byproducts

The widespread use of corn starch and sugarcane as sources of sugar for the production of ethanol via fermentation may negatively impact the use of farmland for production of food. Thus, alternative sources of fermentable sugars, particularly from lignocellulosic sources, have been extensively investigated. Another source of fermentable sugars with substantial potential for ethanol production is the waste from the food growing and processing industry. Reviewed here is the use of waste from potato processing, molasses from processing of sugar beets into sugar, whey from cheese production, byproducts of rice and coffee bean processing, and other food processing wastes as sugar sources for fermentation to ethanol. Specific topics discussed include the organisms used for fermentation, strategies, such as co-culturing and cell immobilization, used to improve the fermentation process, and the use of genetic engineering to improve the performance of ethanol producing fermenters.     

Salmonellae in the Environment Around a Chicken Processing Plant

Studies have been conducted over a 2-year period to determine the extent to which a poultry processing plant served as a reservoir of salmonellae reaching the external environment, to examine the question of the importance of salmonellae in the environment, and to consider how best to control the spread of the organisms. The studies have been undertaken at a chicken processing plant handling between 75,000 and 80,000 birds per day. Populations of salmonellae and indicator bacteria were estimated in the raw wastes, through the waste treatment plant, and in the receiving stream waters. The results demonstrate that salmonellae are present in poultry processing wastes in a surprisingly constant relation to fecal coliforms (in excess of 1 Salmonella per 500 fecal coliforms), that serotypes in the environment are constantly changing, and that they may reflect unusual conditions in the processing plant, or a possible source of infection among human and animal residents of the environment. Disinfection of poultry processing wastes is recommended.     

Salmonellae and pollution indicator bacteria in municipal and food processing effluents and the Cornwallis River

A study was conducted to determine the incidence of fecal coliforms, fecal streptococci, Aeromonas hydrophilia, and Salmonella spp. in the waste discharges of seven sewage treatment plants, four fruit and vegetable canneries, a meat packing plant, a poultry processing plant, and a potato processing plant located along the Cornwallis River in Nova Scotia, Canada. Surface water samples were also collected from 13 locations in the river to assess the impact of these waste discharges on the receiving water quality. The results showed that the final effluents from most of the sewage treatment and processing plants were of very poor bacteriological quality, with the number of indicator bacteria comparable with those found in raw sewage. Salmonellae were isolated from the effluents of the meat and poultry plants and five of the seven sewage treatment plants surveyed. No salmonellae were detected in the effluents of the fruit and vegetable canneries. The impact of the discharge of untreated municipal and food processing wastes on the Cornwallis River water quality was evidenced by the recovery from river water of five Salmonella serotypes, and the high fecal coliform counts which exceeded recommended limit for bathing and shellfish harvesting.     

Bacteria degrading phenolic acids isolated on a polymeric phenolic pigment

Thirty-eight bacterial strains were isolated from waste water of olive oil mills, olives and soil in chemically defined media containing the pigment of these wastes as sole carbon source. Most of the organisms were Pseudomonas spp. Four of the six phenolic acids associated with polymeric pigments in olive oil waste degradation were used by three strains. Only one Pseudomonas strain was able to use five acids.     

Influence of different organic waste materials on the transformation of nitrogen in soils

Organic waste materials like crop residues, well-decomposed cow dung, composts, and other rural and urban wastes are considered highly useful resources in enhancing soil fertility and also in build-up of soil organic matter. Organic matter decomposition provides plant nutrients in soil, which in turn increases crop productivity. Availability of nutrients and nitrogen (N) and phosphorus from organic waste materials is dependent upon the nature of organic residues, climatic conditions, and soil moisture activity. Keeping these factors in view, the present investigation was undertaken to study the transformation of N from different organic waste materials in two contrasting soils from an eastern India, subtropical region. The results showed that the amounts of ammoniacal-N (NH4-N), nitrate-N (NO3-N), hydrolysable N (HL-N), and nonhydrolysable (NHL-N) were increased for up to 60 days of soil submergence and increased further with the increase (1% by weight of soil) of organic residue application. Considering the effect of various organic waste materials, it was found that the amounts of NH4-N, NO3-N, HL-N, and NHL-N were higher with the application of groundnut hull as compared to wheat straw and potato skin, which may be due to relatively narrow carbon:N ratio of groundnut (22:43) than that of wheat straw (62:84) and potato skin (71:32); however, the results showed that the release of NH4-N, NO3-N, HL-N, and NHL-N was in the order of groundnut hull > wheat straw > potato skin.     

Microbial valorization of underutilized and nonconventional waste streams

The growing burden of waste disposal coupled with natural resource scarcity has renewed interest in the remediation, valorization, and/or repurposing of waste. Traditional approaches such as composting, anaerobic digestion, use in fertilizers or animal feed, or incineration for energy production extract very little value out of these waste streams. In contrast, waste valorization into fuels and other biochemicals via microbial fermentation is an area of growing interest. In this review, we discuss microbial valorization of nonconventional, aqueous waste streams such as food processing effluents, wastewater streams, and other industrial wastes. We categorize these waste streams as carbohydrate-rich food wastes, lipid-rich wastes, and other industrial wastes. Recent advances in microbial valorization of these nonconventional waste streams are highlighted, along with a discussion of the specific challenges and opportunities associated with impurities, nitrogen content, toxicity, and low productivity.     

Itaconic Acid Production by Filamentous Fungi in Starch-Rich Industrial Residues

Several fungi and starch-rich industrial residues were screened for itaconic acid (IA) production. Out of 15 strains, only three fungal strains were found to produce IA, which was confirmed by HPLC and GC–MS analysis. These strains were identified as Aspergillus terreus strains C1 and C2, and Ustilago maydis strain C3 by sequencing of 18S rRNA gene and internal transcribed spacer regions. Cis-aconitate decarboxylase (cad) gene, which encodes a key enzyme in IA production in A. terreus, was characterized from strains C1 and C2. C1 and C2 cad gene sequences showed about 96% similarity to the only available GenBank sequence of A. terreus cad gene. 3-D structure and cis-aconitic acid binding pocket of Cad enzyme were predicted by structural modeling. Rice, corn and potato starch wastes were screened for IA production. These materials were enzymatically hydrolyzed under experimentally optimized conditions resulting in the highest glucose production of 230 mg/mL from 20% potato waste. On comparing the production potential of selected strains with different wastes, the best IA production was achieved with strain C1 (255.7 mg/L) using potato waste. Elemental composition as well as batch-to-batch variation in waste substrates were analyzed. The difference in IA production from two different batches of potato waste was found to inversely correlate with their phosphorus content, which indicated that A. terreus produced IA under phosphate limiting condition. The potato waste hydrolysate was deionized to remove inhibitory ions like phosphate, resulting in improved IA production of 4.1 g/L by C1 strain, which is commercially competitive.     

Assessing the addition of mineral processing waste to green waste-derived compost: an agronomic, environmental and economic appraisal

The overall aim of this study was to evaluate the benefit of mixing two large volume wastes, namely mineral processing waste and source-segregated green waste compost, on the growth performance of plants targeted towards high (horticulture/agriculture) and low (amenity/restoration) value markets. The secondary aims were to evaluate the influence of mineral waste type on plant growth performance and to undertake a simple economic analysis of the use of mineral-compost mixtures in land restoration. Our results showed that in comparison to organic wastes, mineral wastes contained a low available nutrient content which reduces compost quality. This is supported by growth trials with tomato, wheat and grass which showed that, irrespective of mineral source, plants performed poorly in compost blended with mineral waste in comparison to those grown in green waste or peat-based compost alone. In terms of consumer confidence, unlike other wastes (e.g. biosolids and construction/demolition waste) the mineral quarry wastes can be expected to be free of potentially toxic elements, however, the production costs of compost-mineral waste mixtures and subsequent transport costs may limit its widespread use. In addition, handling of the material can be difficult under wet conditions and effective blending may require the purchase of specialist equipment. From our results, we conclude that mineral fines may prove useful for low quality, low value landscaping activities close to the source of production but are unsuited to high value markets.     

Induction of biochemical stress markers and apoptosis in transgenic Drosophila melanogaster against complex chemical mixtures: role of reactive oxygen species

The study was aimed to investigate the effect of leachates of solid waste from a flashlight battery factory and a pigment plant on 70 kDa heat shock protein (Hsp70) expression, generation of reactive oxygen species (ROS), antioxidant enzymes activities and apoptosis in Drosophila. Third instar larvae of Drosophila melanogaster transgenic for hsp70 (hsp70-lacZ) were fed on diet mixed with leachates of solid wastes (0.05-2.0%, v/v) released from two industrial plants at three different pHs (7.00, 4.93 and 2.88) for 2-48 h. A concentration- and time-dependent significant change in Hsp70 expression, ROS generation, antioxidant enzymes activities and MDA content was observed in the exposed larvae preceding the antioxidant enzymes activities. Mitochondria-mediated, caspase-dependent apoptotic cell death in the larvae exposed to 1.0 and 2.0% leachates of flashlight battery factory was concurrent with a significant regression in Hsp70 expression and a higher ROS generation. A positive correlation drawn between ROS generation and apoptotic markers and a negative correlation between apoptotic markers and Hsp70 expression in these groups indicated the important role of ROS in the leachate-induced cellular damage. Hsp70 along with antioxidant enzymes offered protection to the organisms exposed to all the tested concentrations of the leachates of pigment plant waste and 0.5% leachate of flashlight battery factory in a cooperative manner when ROS generation was less induced. Conversely, higher levels of ROS generation in the organisms treated with 1.0 and 2.0% leachate of flashlight battery factory after 24 and 48 h resulted in regression of Hsp70 expression in them leading to cell death. The study suggests that (1) leachates of flashlight battery factory waste more adversely affected the organisms in comparison to the leachates of pigment plant waste. (2) Hsp70 may be used as a biomarker of cellular damage in organisms exposed to leachates. (3) Cell based assays using D. melanogaster as an in vivo model may provide important mechanistic information about the adverse effect of xenobiotics.     

海产品加工废弃物再利用研究进展

利用生物技术回收利用海产品加工副产品日益受到国内外研究者的重视。充分回收利用海产品副产品,既可回收废弃资源保护环境,又可带来可观的经济效益。本文综述了国内外海产品加工废弃物再利用现状和存在的问题,以及生物技术在海产品加工废弃物回收再利用中应用的研究进展,并展望了海产加工副产品再利用的发展趋势。     

Production of lactic acid by direct fermentation of starchy wastes by an amylase-producing Lactobacillus

Lactobacillus cellobiosus, isolated from city wastes, produced an extracellular alpha-amylase and produced lactic acid by direct fermentation of waste potato mash. Using a 5% (w/v) potato mash with 3% (w/v) CaCO to neutralise the lactic acid produced, 50% conversion of starch to lactic acid occurred in 48 h without any other media supplement.     

Optimizing edible fungal growth and biodegradation of inedible crop residues using various cropping methods

Long-term manned space flights to Mars require the development of an advanced life support (ALS) ecosystem including efficient food crop production, processing and recycling waste products thereof. Using edible white rot fungi (EWRF) to achieve effective biomass transformation in ALS requires optimal and rapid biodegradative activity on lignocellulosic wastes. We investigated the mycelial growth of Lentinula edodes and Pleurotus ostreatus on processed residues of various crops under various cropping patterns. In single cropping, mycelial growth and fruiting in all strains were significantly repressed on sweet potato and basil. However, growth of the strains was improved when sweet potato and basil residues were paired with rice or wheat straw. Oyster mushroom (Pleurotus) strains were better than shiitake (L. edodes) strains under single, paired, and mixed cropping patterns. Mixed cropping further eliminated the inherent inhibitory effect of sweet potato, basil, or lettuce on fungal growth. Co-cropping fungal species had a synergistic effect on rate of fungal growth, substrate colonization, and fruiting. Use of efficient cropping methods may enhance fungal growth, fruiting, biodegradation of crop residues, and efficiency of biomass recycling.     

Composting of waste from palm oil mill: a sustainable waste management practice

Malaysia is blessed with abundant natural resources and bears a favorable climate for commercial cultivation of crops such as oil palm. In Malaysia the total plantation area of oil palm was 4,487,957 ha in 2008. It has been reported that in 2005 there was a total of 423 palm oil mills having production capacity of approximately 89 million tonnes of fresh fruit bunch (FFB) per year. Waste from the oil palm mill process include palm oil mill effluent (POME), generated mainly from oil extraction, washing and cleaning up processes. POME contains cellulosic material, fat, oil, and grease. Discharging untreated effluent into water streams may cause considerable environmental problems. The solid wastes generated are mainly decanter cake, empty fruit bunches, seed shells and fibre from the mesocarp. POME as well as the solid wastes may rapidly deteriorate the surrounding environment if not dealt with properly. Hence there is an urgent need for a sustainable waste management system to tackle these wastes. As these wastes are organic in origin, they are rich in plant nutrients. Composting of waste generated from palm oil mills can be good practice as it will be helpful in recycling useful plant nutrients. This review deals with various aspects of waste management practices in palm oil mills and the possibility of composting the wastes.     

Effects of acid wastes from titanium dioxide production on biomass and species richness of benthic algae

Titanium dioxide wastes are suspected to be toxic to rocky shore communities in an estuary in southeast Norway. An experimental project lasting two years examined whether titanium dioxide wastes affected recolonization by rocky shore organisms. The experiments were performed in situ in six tanks (each with 9 m³ brackish water) at two different levels of salinity. Three different concentrations of industrial waste water were used. The growth season in 1986 was dry and sunny compared to 1987, causing reduction of growth on exposed granite chips compared to controls. At the two highest waste concentrations in the tanks, Fucus serratus was observed with necrotic tissue both years, and in 1986 benthic diatoms were scarce.     

烟草废弃物在堆肥领域的研究进展

在烟草生产及加工过程中,通常会产生大量的烟草废弃物,如何有效利用这些废弃物以避免环境污染和资源浪费,已成为烟草行业亟需解决的问解。研究发现,烟草废弃物堆肥化处理是规模化利用废弃资源的有效途径之一,对烟草农业的绿色、低碳、循环、可持续发展具有重要意义。从有机肥堆肥制备技术、肥效研究等方面进行了系统综述,从整体上展示了烟草废弃物堆肥技术的发展现状,以期为国内烟草废弃物源堆肥未来技术的研发及产业化提供一定的参考。通过分析发现,在堆肥制备技术方面,主要有微生物菌剂添加技术、共堆肥技术和烟草材料预处理技术3种,此外还衍生出液态有机肥和厌氧发酵联产有机肥技术;在堆肥肥效研究方面,烟草废弃物堆肥可明显改善土壤的物性参数、化学参数以及生物学参数,显著钝化土壤重金属元素,进而提高作物的产量或品质,其中堆肥与化学肥料配施的效果相对较好;堆肥的多功能化是未来堆肥创新利用的重要途径。     

Household Wastes as Larval Habitats of Dengue Vectors: Comparison between Urban and Rural Areas of Kolkata,India

Porcelain and plastic materials constitute bulk of household wastes. Owing to resistibility and slow degradability that accounts for higher residence time, these materials qualify as potential hazardous wastes. Retention of water permits these wastes to form a congenial biotope for the breeding of different vector mosquitoes. Thus porcelain and plastic wastes pose a risk from public health viewpoint. This proposition was validated through the study on the porcelain and plastic household wastes as larval habitats of Dengue vectors (Aedes spp.) in rural and urban areas around Kolkata, India. The wastes were characterized in terms of larval productivity, seasonal variation and a comparison between urban and rural areas was made using data of two subsequent years. The number of wastes positive as larval habitats and their productivity of Aedes spp. varied among the types of household wastes with reference to months and location. Multivariate analysis revealed significant differences in the larval productivity of the household wastes based on the materials, season, and urban–rural context. Results of Discriminant Analysis indicated differences in abundance of Ae. aegypti and Ae. albopictus for the urban and rural areas. The porcelain and plastic wastes were more productive in urban areas compared to the rural areas, indicating a possible difference in the household waste generation. A link between household wastes with Aedes productivity is expected to increase the risk of dengue epidemics if waste generation is continued without appropriate measures to limit addition to the environment. Perhaps, alternative strategies and replacement of materials with low persistence time can reduce this problem of waste and mosquito production.     

Survival of E. coli O157:H7 in organic wastes destined for land application

AIM: To determine the persistence of Escherichia coli O157 in contrasting organic wastes spread to land and to assess the potential environmental risk associated with the disposal of these wastes to land. METHODS AND RESULTS: Twenty-seven organic wastes originating from slaughterhouses, wastewater treatment plants (raw and treated sewage), creameries and farms (bovine slurry), were inoculated with E. coli O157:H7 and incubated at 10 degrees C. Although pathogen numbers gradually declined in all the wastes, albeit at different rates even in the same waste type, E. coli O157:H7 was still viable in 77% of organic wastes tested after 2 months. CONCLUSIONS: Long-term storage of organic wastes led to a significant and gradual decline in E. coli O157:H7 numbers. Consequently, storage may be a useful means of reducing the pathogen load of wastes destined for land application. However, in most cases, long-term storage cannot be expected to completely eliminate E. coli O157:H7 from waste. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results indicate that current legislation may be insufficient to protect the environment from E. coli O157:H7 contamination from untreated wastes spread to land.     

Lytic Enzymes for Gram-negative Bacteria Produced by Bacillus subtilis YT-25

The available energy, gross protein value, phosphorus availability and palatability of 16 samples of single cell protein were evaluated in 20 bioassays using total 2,136 depleted chicks.

Four protein samples were products from Aspergillus tamarii grown on waste water of a fish processing factory, three were from Aspergillus oryzae grown on either acetic acid medium or cooked soybean waste, three were from Candida sp. grown on citrus molasses extracted from peel wastes of citrus processing plants, four were from Candida utitis grown on wood molasses produced from various wood wastes, and two were from Pseudomonas sp. and Alteromonas thlasomethanolica grown on methanol.

Five of 16 samples had excellent nutritive value, comparable to single cell proteins available commercially in Europe. All samples were palatable to the chicks, and no sign of acute toxicity was observed.     

口腔链球菌摄取生物素与口内白色念珠菌生长的关系

为了探讨口腔细菌生态平衡机制,本文体外检测了４株口腔链球菌（Ｓ．ｓａｌｉｖａｒｉｕｓ,Ｓ．ｓａｎｇｕｉｓ,Ｓ．ｍｕｔａｎｓ和Ｓ．ｍｉｔｉｏｒ）和白色念珠菌生长对生物素的依赖性。结果显示白色念珠菌和口腔链球菌的生长绝对依赖生物素,前者最大半数生长需要生物素约１０ｐＭｏｌ／Ｌ,其最大生长率所需生物素约为１００ｐＭｏｌ／Ｌ;而后者最大半数生长需生物素为５２５ｐＭｏｌ／Ｌ。正常人血清和唾液中生物素的含量约为２１２２９４ｐＭｏｌ／Ｌ。生物素饥饿状态下的白色念珠菌和口腔链球菌,以及唾液离心沉淀物（绝大多数为细菌）摄取生物素具温度依赖性,而代谢抑制剂（叠氮化合物、氰化物和醋酸碘）和某些抗生素（杆菌肽、短杆菌肽、万古霉素和二性霉素）具选择性抑制效应,提示生物素的摄取和跨膜转运是一依赖能量的主动过程。用唾液沉淀物和口腔链球菌吸收培养基中的生物素或与白色念珠菌共同培养,显著抑制白色念珠菌的生长。本文首次提供实验证据显示口腔优势菌可能通过竞争生物素等营养成份,抑制白色念珠菌生长,以维持口腔微生物之生态平衡。     

Retention of nutrients by the different wastes produced by the kaolin mining industry in Cornwall

Summary The chemical composition and leaching loss of applied fertilizers were measured from four waste materials derived from china clay extraction. Two waste materials, overburden and mica, had a higher nitrogen and calcium concentration, and were more efficient than sand wastes for the retention of these elements when applied as fertilizers. The possibility of using overburden and mica wastes as amendments for sand waste reclamation is briefly discussed.